Switch docs to MKDocs (#602)

Fixes #601. Merged in 6f87b32 from the md3 branch and did a lot of cleanup.

Changes include:

* Removed old docs build tool, templates, etc.

* Added MkDocs config file, etc.

* filename.txt => filename.md

* pythonhost.org/Markdown => Python-Markdown.github.io

* Markdown lint and other cleanup.

* Automate pages deployment in makefile with `mkdocs gh-deploy`

    Assumes a git remote is set up named "pages". Do

        git remote add pages https://github.com/Python-Markdown/Python-Markdown.github.io.git

    ... before running `make deploy` the first time.

1 files changed, 0 insertions, 115 deletions

diff --git a/docs/index.txt b/docs/index.txt
deleted file mode 100644
index 92ac2d0..0000000
--- a/docs/index.txt
+++ /dev/null
@@ -1,115 +0,0 @@
-next_url:   install.html
-next_title: Installation
-prev_title: Table of Contents
-prev_url:   siteindex.html
-
-Python-Markdown
-===============
-
-This is a Python implementation of John Gruber's 
-[Markdown](http://daringfireball.net/projects/markdown/). 
-It is almost completely compliant with the reference implementation,
-though there are a few very minor [differences](#differences). See John's 
-[Syntax Documentation](http://daringfireball.net/projects/markdown/syntax) 
-for the syntax rules.
-
-See the [installation instructions](install.html) to get started.
-
-Goals
------
-
-The Python-Markdown project is developed with the following goals in mind:
-
-* Maintain a Python 2 *and* Python 3 library (with an optional CLI wrapper)
-  suited to use in web server environments (never raise an exception, never 
-  write to stdout, etc.) as an implementation of the markdown parser that 
-  follows the [syntax rules](http://daringfireball.net/projects/markdown/syntax)
-  and the behavior of the original (markdown.pl) implementation as reasonably
-  as possible (see [differences](#differences) for a few exceptions).
-
-* Provide an [Extension API](extensions/api.html) which makes it possible
-  to change and/or extend the behavior of the parser.
-
-Features
---------
-
-In addition to the basic markdown syntax, Python-Markdown supports the following
-features:
-
-* __International Input__
-
-    Python-Markdown will accept [input](reference.html#text) in any language 
-    supported by Unicode including bi-directional text. In fact the test suite 
-    includes documents written in Russian and Arabic.
-
-* __Extensions__
-
-    Various [extensions](extensions/index.html) are provided (including 
-    [extra](extensions/extra.html)) to change and/or extend the base syntax. 
-    Additionally, a public [Extension API](extensions/api.html) is available 
-    to write your own extensions.
-
-* __Output Formats__
-
-    Python-Markdown can output documents in HTML4, XHTML and HTML5. See the
-    [Library Reference](reference.html#output_format) for details.
-
-* __Command Line Interface__
-
-    In addition to being a Python Library, a 
-    [command line script](cli.html) is available for your convenience.
-
-Differences
------------
-
-While Python-Markdown strives to fully implement markdown as described in the 
-[syntax rules](http://daringfireball.net/projects/markdown/syntax), the rules 
-can be interpreted in different ways and different implementations 
-occasionally vary in their behavior (see the 
-[Babelmark FAQ](http://johnmacfarlane.net/babelmark2/faq.html#what-are-some-examples-of-interesting-divergences-between-implementations)
-for some examples). Known and intentional differences found in Python-Markdown 
-are summarized below:
-
-* __Middle-Word Emphasis__
-
-    Python-Markdown defaults to ignoring middle-word emphasis. In other words,
-    `some_long_filename.txt` will not become `some<em>long</em>filename.txt`.
-    This can be switched off if desired. See the 
-    [Library Reference](reference.html#smart_emphasis) for details.
-
-* __Indentation/Tab Length__
-
-    The [syntax rules](http://daringfireball.net/projects/markdown/syntax#list) 
-    clearly state that when a list item consists of multiple paragraphs, "each 
-    subsequent paragraph in a list item **must** be indented by either 4 spaces 
-    or one tab" (emphasis added). However, many implementations do not enforce 
-    this rule and allow less than 4 spaces of indentation. The implementers of 
-    Python-Markdown consider it a bug to not enforce this rule. 
-
-    This applies to any block level elements nested in a list, including
-    paragraphs, sub-lists, blockquotes, code blocks, etc. They **must** always 
-    be indented by at least four spaces (or one tab) for each level of nesting.
-
-    In the event that one would prefer different behavior,
-    [tab_length](reference.html#tab_length) can be set to whatever length is 
-    desired. Be warned however, as this will affect indentation for all aspects 
-    of the syntax (including root level code blocks).
-
-* __Consecutive Lists__
-
-    While the syntax rules are not clear on this, many implementations (including 
-    the original) do not end one list and start a second list when the list marker
-    (asterisks, pluses, hyphens, and numbers) changes. For consistency, 
-    Python-Markdown maintains the same behavior with no plans to change in the 
-    foreseeable future. That said, the [Sane List Extension](extensions/sane_lists.html)
-    is available to provide a less surprising behavior.
-    
-
-Support
--------
-
-You may ask for help and discuss various other issues on the [mailing list][] 
-and report bugs on the [bug tracker][].
-
-[mailing list]: http://lists.sourceforge.net/lists/listinfo/python-markdown-discuss
-[bug tracker]: http://github.com/Python-Markdown/markdown/issues