user/jszakmeister: update clojure snippets

These are converted from David Nolen's clojure-snippets repo for
Yasnippets:
    https://github.com/swannodette/clojure-snippets
Point to Szakmeister's implementation of rst2ctags.
Replace syntax/mkd.vim with vim-markdown.

This also includes incorporating some of vim-markdown's setting into our
SetupMarkdown(), and adding a little extra highlighting for code blocks.
Make the default filetype for Markdown files be "markdown".

It appears "markdown" is a more common filetype for markdown files, so
it seems to be a better default.  To provide some support for mkd, just
in case, mkd snippets now delegates to markdown.

This change also means that anyone with custom mkd snippets and
autocommands needs to change them to markdown instead.

Also, we now use vim-markdown's filetype detection.  Now .mkdn is
recognized as a markdown filetype and now .mdwn is not.  This seems
reasonable since .mdwn seems unlikely to be used.
user/jszakmeister: move markdown snippets to the new filetype
Implement better embedded language support for vim-markdown.
Support embeddeding sh and vim in rst and markdown documents.
user/jszakmeister: enable support for trac-style code blocks in markdown
Merge branch 'js/update-markdown'
Merge branch 'js/mine'
user/jszakmeister: add a command to edit the correct snippets.py file
Add CHANGES.txt file and consolidate installation instructions.

README.txt now merely points into doc/notes.txt where all of the
instructions live.
Update to v0.1.1 of rst2ctags.

TagBar treats empty output from a ctags-like executable as though it
were unsuccessful.  This version will now emit the headers to stdout.
user/jszakmeister: add a couple of rst snippets for my backlog files
user/jszakmeister: add some snippets for clojure, markdown, and python
Avoid wasting time setting up menus since I disable them for drmikehenry.
Add vim-fontdetect plugin to fix broken font fallback logic.
Integrate fontdetect into jszakmeister settings.
Update vim-fontdetect to 0.2.0 (fall back to fc-list on OS X).
Update to a newer version of TagBar.

This one includes the fix to avoid forcefully re-running ctags
generation on BufReadPost.