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, 230 deletions

diff --git a/docs/change_log.txt b/docs/change_log.txt
deleted file mode 100644
index c9478a2..0000000
--- a/docs/change_log.txt
+++ /dev/null
@@ -1,230 +0,0 @@
-title:      Change Log
-prev_title: Test Suite
-prev_url:   test_suite.html
-next_title: Release Notes for v2.6
-next_url:   release-2.6.html
-
-Python-Markdown Change Log
-=========================
-
-Aug 17, 2017: Released version 2.6.9 (a bug-fix release).
-
-Jan 25, 2017: Released version 2.6.8 (a bug-fix release).
-
-Sept 23, 2016: Released version 2.6.7 (a bug-fix release).
-
-Mar 20, 2016: Released version 2.6.6 (a bug-fix release).
-
-Nov 24, 2015: Released version 2.6.5 (a bug-fix release).
-
-Nov 6, 2015: Released version 2.6.4 (a bug-fix release).
-
-Oct 26, 2015: Released version 2.6.3 (a bug-fix release).
-
-Apr 20, 2015: Released version 2.6.2 (a bug-fix release).
-
-Mar 8, 2015: Released version 2.6.1 (a bug-fix release). The (new)
-`yaml` option has been removed from the Meta-Data Extension as it was buggy
-(see [#390](https://github.com/Python-Markdown/markdown/issues/390)).
-
-Feb 19, 2015: Released version 2.6 ([Notes](release-2.6.html)).
-
-Nov 19, 2014: Released version 2.5.2 (a bug-fix release).
-
-Sept 26, 2014: Released version 2.5.1 (a bug-fix release).
-
-Sept 12, 2014: Released version 2.5.0 ([Notes](release-2.5.html)).
-
-Feb 16, 2014: Released version 2.4.0 ([Notes](release-2.4.html)).
-
-Mar 22, 2013: Released version 2.3.1 (a bug-fix release).
-
-Mar 14, 2013: Released version 2.3.0 ([Notes](release-2.3.html))
-
-Nov 4, 2012: Released version 2.2.1 ([Notes](release-2.2.1.html)).
-
-Jul 5, 2012: Released version 2.2.0 ([Notes](release-2.2.0.html)).
-
-Jan 22, 2012: Released version 2.1.1 ([Notes](release-2.1.1.html)).
-
-Nov 24, 2011: Released version 2.1.0 ([Notes](release-2.1.0.html)).
-
-Oct 7, 2009: Released version 2.0.3.
-
-Sept 28, 2009: Released version 2.0.2 ([Notes](release-2.0.2.html)).
-
-May 20, 2009: Released version 2.0.1 ([Notes](release-2.0.1.html)).
-
-Mar 30, 2009: Released version 2.0 ([Notes](release-2.0.html)).
-
-Mar 8, 2009: Release Candidate 2.0-rc-1.
-
-Feb 2009: Added support for multi-level lists to new Blockprocessors.
-
-Jan 2009: Added HTML 4 output as an option (thanks Eric Abrahamsen)
-
-Nov 2008: Added Definition List ext. Replaced old core with Blockprocessors.
-Broken up into multiple files.
-
-Oct 2008: Changed logging behavior to work better with other systems.
-Refactored tree traversing. Added `treap` implementation, then replaced with
-OrderedDict. Renamed various processors to better reflect what they actually
-do. Refactored footnote ext to match PHP Extra's output.
-
-Sept 2008: Moved `prettifyTree` to a Postprocessor, replaced WikiLink ext
-with WikiLinks (note the s) ext (uses bracketed links instead of CamelCase)
-and various bug fixes.
-
-August 18 2008: Reorganized directory structure. Added a 'docs' directory
-and moved all extensions into a 'markdown-extensions' package.
-Added additional documentation and a few bug fixes. (v2.0-beta)
-
-August 4 2008: Updated included extensions to ElementTree. Added a
-separate command line script. (v2.0-alpha)
-
-July 2008: Switched from home-grown NanoDOM to ElementTree and
-various related bugs (thanks Artem Yunusov).
-
-June 2008: Fixed issues with nested inline patterns and cleaned
-up testing framework (thanks Artem Yunusov).
-
-May 2008: Added a number of additional extensions to the
-distribution and other minor changes. Moved repository to git from svn.
-
-Mar 2008: Refactored extension API to accept either an
-extension name (as a string) or an instance of an extension
-(Thanks David Wolever). Fixed various bugs and added doc strings.
-
-Feb 2008: Various bug-fixes mostly regarding extensions.
-
-Feb 18, 2008: Version 1.7.
-
-Feb 13, 2008: A little code cleanup and better documentation
-and inheritance for Preprocessors/Postprocessors.
-
-Feb 9, 2008: Double-quotes no longer HTML escaped and raw HTML
-honors `<?foo>`, `<@foo>`, and `<%foo>` for those who run markdown on
-template syntax.
-
-Dec 12, 2007: Updated docs. Removed encoding argument from Markdown
-and markdown as per list discussion. Clean up in prep for 1.7.
-
-Nov 29, 2007: Added support for images inside links. Also fixed
-a few bugs in the footnote extension.
-
-Nov 19, 2007: `message` now uses python's logging module. Also removed
-limit imposed by recursion in `_process_section()`. You can now parse as
-long of a document as your memory can handle.
-
-Nov 5, 2007: Moved `safe_mode` code to a `textPostprocessor` and added
-escaping option.
-
-Nov 3, 2007: Fixed convert method to accept empty strings.
-
-Oct 30, 2007: Fixed `BOM` removal (thanks Malcolm Tredinnick). Fixed
-infinite loop in bracket regular expression for inline links.
-
-Oct 11, 2007: `LineBreaks` is now an `inlinePattern`. Fixed `HR` in
-blockquotes. Refactored `_processSection` method (see tracker #1793419).
-
-Oct 9, 2007: Added `textPreprocessor` (from 1.6b).
-
-Oct 8, 2008: Fixed Lazy Blockquote. Fixed code block on first line.
-Fixed empty inline image link.
-
-Oct 7, 2007: Limit recursion on inline patterns. Added a 'safe' tag
-to `htmlStash`.
-
-March 18, 2007: Fixed or merged a bunch of minor bugs, including
-multi-line comments and markup inside links. (Tracker #s: 1683066,
-1671153, 1661751, 1627935, 1544371, 1458139.) -> v. 1.6b
-
-Oct 10, 2006: Fixed a bug that caused some text to be lost after
-comments.  Added "safe mode" (user's HTML tags are removed).
-
-Sept 6, 2006: Added exception for PHP tags when handling HTML blocks.
-
-August 7, 2006: Incorporated Sergej Chodarev's patch to fix a problem
-with ampersand normalization and HTML blocks.
-
-July 10, 2006: Switched to using `optparse`.  Added proper support for
-Unicode.
-
-July 9, 2006: Fixed the `<!--@address.com>` problem (Tracker #1501354).
-
-May 18, 2006: Stopped catching unquoted titles in reference links.
-Stopped creating blank headers.
-
-May 15, 2006: A bug with lists, recursion on block-level elements,
-run-in headers, spaces before headers, Unicode input (thanks to Aaron
-Swartz). Sourceforge tracker #s: 1489313, 1489312, 1489311, 1488370,
-1485178, 1485176. (v. 1.5)
-
-Mar. 24, 2006: Switched to a not-so-recursive algorithm with
-`_handleInline`.  (Version 1.4)
-
-Mar. 15, 2006: Replaced some instance variables with class variables
-(a patch from Stelios Xanthakis).  Chris Clark's new regexps that do
-not trigger mid-word underlining.
-
-Feb. 28, 2006: Clean-up and command-line handling by Stewart
-Midwinter. (Version 1.3)
-
-Feb. 24, 2006: Fixed a bug with the last line of the list appearing
-again as a separate paragraph.  Incorporated Chris Clark's "mail-to"
-patch.  Added support for `<br />` at the end of lines ending in two or
-more spaces.  Fixed a crashing bug when using `ImageReferencePattern`.
-Added several utility methods to `Nanodom`.  (Version 1.2)
-
-Jan. 31, 2006: Added `hr` and `hr/` to BLOCK_LEVEL_ELEMENTS and
-changed `<hr/>` to `<hr />`.  (Thanks to Sergej Chodarev.)
-
-Nov. 26, 2005: Fixed a bug with certain tabbed lines inside lists
-getting wrapped in `<pre><code>`.  (v. 1.1)
-
-Nov. 19, 2005: Made `<!...`, `<?...`, etc. behave like block-level
-HTML tags.
-
-Nov. 14, 2005: Added entity code and email auto-link fix by Tiago
-Cogumbreiro.  Fixed some small issues with backticks to get 100%
-compliance with John's test suite.  (v. 1.0)
-
-Nov. 7, 2005: Added an `unlink` method for documents to aid with memory
-collection (per Doug Sauder's suggestion).
-
-Oct. 29, 2005: Restricted a set of HTML tags that get treated as
-block-level elements.
-
-Sept. 18, 2005: Refactored the whole script to make it easier to
-customize it and made footnote functionality into an extension.
-(v. 0.9)
-
-Sept. 5, 2005: Fixed a bug with multi-paragraph footnotes.  Added
-attribute support.
-
-Sept. 1, 2005: Changed the way headers are handled to allow inline
-syntax in headers (e.g. links) and got the lists to use p-tags
-correctly (v. 0.8)
-
-Aug. 29, 2005: Added flexible tabs, fixed a few small issues, added
-basic support for footnotes.  Got rid of xml.dom.minidom and added
-pretty-printing. (v. 0.7)
-
-Aug. 13, 2005: Fixed a number of small bugs in order to conform to the
-test suite.  (v. 0.6)
-
-Aug. 11, 2005: Added support for inline HTML and entities, inline
-images, auto-links, underscore emphasis. Cleaned up and refactored the
-code, added some more comments.
-
-Feb. 19, 2005: Rewrote the handling of high-level elements to allow
-multi-line list items and all sorts of nesting.
-
-Feb. 3, 2005: Reference-style links, single-line lists, backticks,
-escape, emphasis in the beginning of the paragraph.
-
-Nov. 2004: Added links, blockquotes, HTML blocks to Manfred
-Stienstra's code
-
-Apr. 2004: Manfred's version at <http://www.dwerg.net/projects/markdown/>
-