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1. GNU Free Documentation License {#gnu-free-documentation-license .chapter}
=================================

Version 1.3, 3 November 2008

+--------------------------------------+--------------------------------------+
|                                      | ``` {.display}                       |
|                                      | Copyright © 2000, 2001, 2002, 2007,  |
|                                      | 2008 Free Software Foundation, Inc.  |
|                                      | http://fsf.org/                      |
|                                      |                                      |
|                                      | Everyone is permitted to copy and di |
|                                      | stribute verbatim copies             |
|                                      | of this license document, but changi |
|                                      | ng it is not allowed.                |
|                                      | ```                                  |
+--------------------------------------+--------------------------------------+

1.  **PREAMBLE**

    The purpose of this License is to make a manual, textbook, or other
    functional and useful document *free* in the sense of freedom: to
    assure everyone the effective freedom to copy and redistribute it,
    with or without modifying it, either commercially
    or noncommercially. Secondarily, this License preserves for the
    author and publisher a way to get credit for their work, while not
    being considered responsible for modifications made by others.

    This License is a kind of “copyleft”, which means that derivative
    works of the document must themselves be free in the same sense. It
    complements the GNU General Public License, which is a copyleft
    license designed for free software.

    We have designed this License in order to use it for manuals for
    free software, because free software needs free documentation: a
    free program should come with manuals providing the same freedoms
    that the software does. But this License is not limited to software
    manuals; it can be used for any textual work, regardless of subject
    matter or whether it is published as a printed book. We recommend
    this License principally for works whose purpose is instruction
    or reference.

2.  **APPLICABILITY AND DEFINITIONS**

    This License applies to any manual or other work, in any medium,
    that contains a notice placed by the copyright holder saying it can
    be distributed under the terms of this License. Such a notice grants
    a world-wide, royalty-free license, unlimited in duration, to use
    that work under the conditions stated herein. The “Document”, below,
    refers to any such manual or work. Any member of the public is a
    licensee, and is addressed as “you”. You accept the license if you
    copy, modify or distribute the work in a way requiring permission
    under copyright law.

    A “Modified Version” of the Document means any work containing the
    Document or a portion of it, either copied verbatim, or with
    modifications and/or translated into another language.

    A “Secondary Section” is a named appendix or a front-matter section
    of the Document that deals exclusively with the relationship of the
    publishers or authors of the Document to the Document’s overall
    subject (or to related matters) and contains nothing that could fall
    directly within that overall subject. (Thus, if the Document is in
    part a textbook of mathematics, a Secondary Section may not explain
    any mathematics.) The relationship could be a matter of historical
    connection with the subject or with related matters, or of legal,
    commercial, philosophical, ethical or political position
    regarding them.

    The “Invariant Sections” are certain Secondary Sections whose titles
    are designated, as being those of Invariant Sections, in the notice
    that says that the Document is released under this License. If a
    section does not fit the above definition of Secondary then it is
    not allowed to be designated as Invariant. The Document may contain
    zero Invariant Sections. If the Document does not identify any
    Invariant Sections then there are none.

    The “Cover Texts” are certain short passages of text that are
    listed, as Front-Cover Texts or Back-Cover Texts, in the notice that
    says that the Document is released under this License. A Front-Cover
    Text may be at most 5 words, and a Back-Cover Text may be at most
    25 words.

    A “Transparent” copy of the Document means a machine-readable copy,
    represented in a format whose specification is available to the
    general public, that is suitable for revising the document
    straightforwardly with generic text editors or (for images composed
    of pixels) generic paint programs or (for drawings) some widely
    available drawing editor, and that is suitable for input to text
    formatters or for automatic translation to a variety of formats
    suitable for input to text formatters. A copy made in an otherwise
    Transparent file format whose markup, or absence of markup, has been
    arranged to thwart or discourage subsequent modification by readers
    is not Transparent. An image format is not Transparent if used for
    any substantial amount of text. A copy that is not “Transparent” is
    called “Opaque”.

    Examples of suitable formats for Transparent copies include plain
    ASCII without markup, Texinfo input format, LaTeX input format, SGML
    or XML using a publicly available DTD, and standard-conforming
    simple HTML, PostScript or PDF designed for human modification.
    Examples of transparent image formats include PNG, XCF and JPG.
    Opaque formats include proprietary formats that can be read and
    edited only by proprietary word processors, SGML or XML for which
    the DTD and/or processing tools are not generally available, and the
    machine-generated HTML, PostScript or PDF produced by some word
    processors for output purposes only.

    The “Title Page” means, for a printed book, the title page itself,
    plus such following pages as are needed to hold, legibly, the
    material this License requires to appear in the title page. For
    works in formats which do not have any title page as such, “Title
    Page” means the text near the most prominent appearance of the
    work’s title, preceding the beginning of the body of the text.

    The “publisher” means any person or entity that distributes copies
    of the Document to the public.

    A section “Entitled XYZ” means a named subunit of the Document whose
    title either is precisely XYZ or contains XYZ in parentheses
    following text that translates XYZ in another language. (Here XYZ
    stands for a specific section name mentioned below, such as
    “Acknowledgements”, “Dedications”, “Endorsements”, or “History”.) To
    “Preserve the Title” of such a section when you modify the Document
    means that it remains a section “Entitled XYZ” according to
    this definition.

    The Document may include Warranty Disclaimers next to the notice
    which states that this License applies to the Document. These
    Warranty Disclaimers are considered to be included by reference in
    this License, but only as regards disclaiming warranties: any other
    implication that these Warranty Disclaimers may have is void and has
    no effect on the meaning of this License.

3.  **VERBATIM COPYING**

    You may copy and distribute the Document in any medium, either
    commercially or noncommercially, provided that this License, the
    copyright notices, and the license notice saying this License
    applies to the Document are reproduced in all copies, and that you
    add no other conditions whatsoever to those of this License. You may
    not use technical measures to obstruct or control the reading or
    further copying of the copies you make or distribute. However, you
    may accept compensation in exchange for copies. If you distribute a
    large enough number of copies you must also follow the conditions in
    section 3.

    You may also lend copies, under the same conditions stated above,
    and you may publicly display copies.

4.  **COPYING IN QUANTITY**

    If you publish printed copies (or copies in media that commonly have
    printed covers) of the Document, numbering more than 100, and the
    Document’s license notice requires Cover Texts, you must enclose the
    copies in covers that carry, clearly and legibly, all these Cover
    Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
    the back cover. Both covers must also clearly and legibly identify
    you as the publisher of these copies. The front cover must present
    the full title with all words of the title equally prominent
    and visible. You may add other material on the covers in addition.
    Copying with changes limited to the covers, as long as they preserve
    the title of the Document and satisfy these conditions, can be
    treated as verbatim copying in other respects.

    If the required texts for either cover are too voluminous to fit
    legibly, you should put the first ones listed (as many as
    fit reasonably) on the actual cover, and continue the rest onto
    adjacent pages.

    If you publish or distribute Opaque copies of the Document numbering
    more than 100, you must either include a machine-readable
    Transparent copy along with each Opaque copy, or state in or with
    each Opaque copy a computer-network location from which the general
    network-using public has access to download using public-standard
    network protocols a complete Transparent copy of the Document, free
    of added material. If you use the latter option, you must take
    reasonably prudent steps, when you begin distribution of Opaque
    copies in quantity, to ensure that this Transparent copy will remain
    thus accessible at the stated location until at least one year after
    the last time you distribute an Opaque copy (directly or through
    your agents or retailers) of that edition to the public.

    It is requested, but not required, that you contact the authors of
    the Document well before redistributing any large number of copies,
    to give them a chance to provide you with an updated version of
    the Document.

5.  **MODIFICATIONS**

    You may copy and distribute a Modified Version of the Document under
    the conditions of sections 2 and 3 above, provided that you release
    the Modified Version under precisely this License, with the Modified
    Version filling the role of the Document, thus licensing
    distribution and modification of the Modified Version to whoever
    possesses a copy of it. In addition, you must do these things in the
    Modified Version:

    1.  Use in the Title Page (and on the covers, if any) a title
        distinct from that of the Document, and from those of previous
        versions (which should, if there were any, be listed in the
        History section of the Document). You may use the same title as
        a previous version if the original publisher of that version
        gives permission.
    2.  List on the Title Page, as authors, one or more persons or
        entities responsible for authorship of the modifications in the
        Modified Version, together with at least five of the principal
        authors of the Document (all of its principal authors, if it has
        fewer than five), unless they release you from this requirement.
    3.  State on the Title page the name of the publisher of the
        Modified Version, as the publisher.
    4.  Preserve all the copyright notices of the Document.
    5.  Add an appropriate copyright notice for your modifications
        adjacent to the other copyright notices.
    6.  Include, immediately after the copyright notices, a license
        notice giving the public permission to use the Modified Version
        under the terms of this License, in the form shown in the
        Addendum below.
    7.  Preserve in that license notice the full lists of Invariant
        Sections and required Cover Texts given in the Document’s
        license notice.
    8.  Include an unaltered copy of this License.
    9.  Preserve the section Entitled “History”, Preserve its Title, and
        add to it an item stating at least the title, year, new authors,
        and publisher of the Modified Version as given on the
        Title Page. If there is no section Entitled “History” in the
        Document, create one stating the title, year, authors, and
        publisher of the Document as given on its Title Page, then add
        an item describing the Modified Version as stated in the
        previous sentence.
    10. Preserve the network location, if any, given in the Document for
        public access to a Transparent copy of the Document, and
        likewise the network locations given in the Document for
        previous versions it was based on. These may be placed in the
        “History” section. You may omit a network location for a work
        that was published at least four years before the Document
        itself, or if the original publisher of the version it refers to
        gives permission.
    11. For any section Entitled “Acknowledgements” or “Dedications”,
        Preserve the Title of the section, and preserve in the section
        all the substance and tone of each of the contributor
        acknowledgements and/or dedications given therein.
    12. Preserve all the Invariant Sections of the Document, unaltered
        in their text and in their titles. Section numbers or the
        equivalent are not considered part of the section titles.
    13. Delete any section Entitled “Endorsements”. Such a section may
        not be included in the Modified Version.
    14. Do not retitle any existing section to be Entitled
        “Endorsements” or to conflict in title with any
        Invariant Section.
    15. Preserve any Warranty Disclaimers.

    If the Modified Version includes new front-matter sections or
    appendices that qualify as Secondary Sections and contain no
    material copied from the Document, you may at your option designate
    some or all of these sections as invariant. To do this, add their
    titles to the list of Invariant Sections in the Modified Version’s
    license notice. These titles must be distinct from any other
    section titles.

    You may add a section Entitled “Endorsements”, provided it contains
    nothing but endorsements of your Modified Version by various
    parties—for example, statements of peer review or that the text has
    been approved by an organization as the authoritative definition of
    a standard.

    You may add a passage of up to five words as a Front-Cover Text, and
    a passage of up to 25 words as a Back-Cover Text, to the end of the
    list of Cover Texts in the Modified Version. Only one passage of
    Front-Cover Text and one of Back-Cover Text may be added by (or
    through arrangements made by) any one entity. If the Document
    already includes a cover text for the same cover, previously added
    by you or by arrangement made by the same entity you are acting on
    behalf of, you may not add another; but you may replace the old one,
    on explicit permission from the previous publisher that added the
    old one.

    The author(s) and publisher(s) of the Document do not by this
    License give permission to use their names for publicity for or to
    assert or imply endorsement of any Modified Version.

6.  **COMBINING DOCUMENTS**

    You may combine the Document with other documents released under
    this License, under the terms defined in section 4 above for
    modified versions, provided that you include in the combination all
    of the Invariant Sections of all of the original documents,
    unmodified, and list them all as Invariant Sections of your combined
    work in its license notice, and that you preserve all their
    Warranty Disclaimers.

    The combined work need only contain one copy of this License, and
    multiple identical Invariant Sections may be replaced with a
    single copy. If there are multiple Invariant Sections with the same
    name but different contents, make the title of each such section
    unique by adding at the end of it, in parentheses, the name of the
    original author or publisher of that section if known, or else a
    unique number. Make the same adjustment to the section titles in the
    list of Invariant Sections in the license notice of the
    combined work.

    In the combination, you must combine any sections Entitled “History”
    in the various original documents, forming one section Entitled
    “History”; likewise combine any sections Entitled
    “Acknowledgements”, and any sections Entitled “Dedications”. You
    must delete all sections Entitled “Endorsements.”

7.  **COLLECTIONS OF DOCUMENTS**

    You may make a collection consisting of the Document and other
    documents released under this License, and replace the individual
    copies of this License in the various documents with a single copy
    that is included in the collection, provided that you follow the
    rules of this License for verbatim copying of each of the documents
    in all other respects.

    You may extract a single document from such a collection, and
    distribute it individually under this License, provided you insert a
    copy of this License into the extracted document, and follow this
    License in all other respects regarding verbatim copying of
    that document.

8.  **AGGREGATION WITH INDEPENDENT WORKS**

    A compilation of the Document or its derivatives with other separate
    and independent documents or works, in or on a volume of a storage
    or distribution medium, is called an “aggregate” if the copyright
    resulting from the compilation is not used to limit the legal rights
    of the compilation’s users beyond what the individual works permit.
    When the Document is included in an aggregate, this License does not
    apply to the other works in the aggregate which are not themselves
    derivative works of the Document.

    If the Cover Text requirement of section 3 is applicable to these
    copies of the Document, then if the Document is less than one half
    of the entire aggregate, the Document’s Cover Texts may be placed on
    covers that bracket the Document within the aggregate, or the
    electronic equivalent of covers if the Document is in
    electronic form. Otherwise they must appear on printed covers that
    bracket the whole aggregate.

9.  **TRANSLATION**

    Translation is considered a kind of modification, so you may
    distribute translations of the Document under the terms of
    section 4. Replacing Invariant Sections with translations requires
    special permission from their copyright holders, but you may include
    translations of some or all Invariant Sections in addition to the
    original versions of these Invariant Sections. You may include a
    translation of this License, and all the license notices in the
    Document, and any Warranty Disclaimers, provided that you also
    include the original English version of this License and the
    original versions of those notices and disclaimers. In case of a
    disagreement between the translation and the original version of
    this License or a notice or disclaimer, the original version
    will prevail.

    If a section in the Document is Entitled “Acknowledgements”,
    “Dedications”, or “History”, the requirement (section 4) to Preserve
    its Title (section 1) will typically require changing the
    actual title.

10. **TERMINATION**

    You may not copy, modify, sublicense, or distribute the Document
    except as expressly provided under this License. Any attempt
    otherwise to copy, modify, sublicense, or distribute it is void, and
    will automatically terminate your rights under this License.

    However, if you cease all violation of this License, then your
    license from a particular copyright holder is reinstated (a)
    provisionally, unless and until the copyright holder explicitly and
    finally terminates your license, and (b) permanently, if the
    copyright holder fails to notify you of the violation by some
    reasonable means prior to 60 days after the cessation.

    Moreover, your license from a particular copyright holder is
    reinstated permanently if the copyright holder notifies you of the
    violation by some reasonable means, this is the first time you have
    received notice of violation of this License (for any work) from
    that copyright holder, and you cure the violation prior to 30 days
    after your receipt of the notice.

    Termination of your rights under this section does not terminate the
    licenses of parties who have received copies or rights from you
    under this License. If your rights have been terminated and not
    permanently reinstated, receipt of a copy of some or all of the same
    material does not give you any rights to use it.

11. **FUTURE REVISIONS OF THIS LICENSE**

    The Free Software Foundation may publish new, revised versions of
    the GNU Free Documentation License from time to time. Such new
    versions will be similar in spirit to the present version, but may
    differ in detail to address new problems or concerns. See
    <http://www.gnu.org/copyleft/>.

    Each version of the License is given a distinguishing
    version number. If the Document specifies that a particular numbered
    version of this License “or any later version” applies to it, you
    have the option of following the terms and conditions either of that
    specified version or of any later version that has been published
    (not as a draft) by the Free Software Foundation. If the Document
    does not specify a version number of this License, you may choose
    any version ever published (not as a draft) by the Free
    Software Foundation. If the Document specifies that a proxy can
    decide which future versions of this License can be used, that
    proxy’s public statement of acceptance of a version permanently
    authorizes you to choose that version for the Document.

12. **RELICENSING**

    “Massive Multiauthor Collaboration Site” (or “MMC Site”) means any
    World Wide Web server that publishes copyrightable works and also
    provides prominent facilities for anybody to edit those works. A
    public wiki that anybody can edit is an example of such a server. A
    “Massive Multiauthor Collaboration” (or “MMC”) contained in the site
    means any set of copyrightable works thus published on the MMC site.

    “CC-BY-SA” means the Creative Commons Attribution-Share Alike 3.0
    license published by Creative Commons Corporation, a not-for-profit
    corporation with a principal place of business in San Francisco,
    California, as well as future copyleft versions of that license
    published by that same organization.

    “Incorporate” means to publish or republish a Document, in whole or
    in part, as part of another Document.

    An MMC is “eligible for relicensing” if it is licensed under this
    License, and if all works that were first published under this
    License somewhere other than this MMC, and subsequently incorporated
    in whole or in part into the MMC, (1) had no cover texts or
    invariant sections, and (2) were thus incorporated prior to November
    1, 2008.

    The operator of an MMC Site may republish an MMC contained in the
    site under CC-BY-SA on the same site at any time before August 1,
    2009, provided the MMC is eligible for relicensing.

ADDENDUM: How to use this License for your documents {#addendum-how-to-use-this-license-for-your-documents .heading}
----------------------------------------------------

To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and license
notices just after the title page:

+--------------------------------------+--------------------------------------+
|                                      | ``` {.smallexample}                  |
|                                      | Copyright (C)  year  your name.      |
|                                      | Permission is granted to copy, distr |
|                                      | ibute and/or modify this document    |
|                                      | under the terms of the GNU Free Docu |
|                                      | mentation License, Version 1.3 or    |
|                                      | any later version published by the F |
|                                      | ree Software Foundation; with        |
|                                      | no Invariant Sections, no Front-Cove |
|                                      | r Texts, and no Back-Cover Texts.    |
|                                      | A copy of the license is included in |
|                                      |  the section entitled                |
|                                      | ``GNU Free Documentation License''.  |
|                                      | ```                                  |
+--------------------------------------+--------------------------------------+

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
replace the “with…Texts.” line with this:

+--------------------------------------+--------------------------------------+
|                                      | ``` {.smallexample}                  |
|                                      |     with the Invariant Sections bein |
|                                      | g list their titles, with            |
|                                      |     the Front-Cover Texts being list |
|                                      | , and with the Back-Cover Texts      |
|                                      |     being list.                      |
|                                      | ```                                  |
+--------------------------------------+--------------------------------------+

If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
situation.

If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of free
software license, such as the GNU General Public License, to permit
their use in free software.

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