Markdown2

- New "tables" extra for table syntax that matches GFM
<https://help.github.com/articles/github-flavored-markdown#tables> and
PHP-Markdown Extra <https://michelf.ca/projects/php-markdown/extra/#table>.
For example:

| Header 1 | *Header* 2 |
| -------- | -------- |
| `Cell 1` | [Cell 2](http://example.com) link |
| Cell 3 | **Cell 4** |

See <https://github.com/trentm/python-markdown2/blob/master/test/tm-cases/tables.text>
for examples and edge cases.

If you have documents using the 'wiki-tables' syntax and want to convert to the
'tables' syntax, there is a script to help with that here:
<https://github.com/trentm/python-markdown2/blob/master/tools/wiki-tables-to-tables.py>

- [issue 165] Fix an edge case in list parsing.

- [pull 156] Footnotes XML compatibility.
- [pull 157] Horizontal rule minimum length.
- [pull 162] Fix escaping fenced code block with safe mode
- [pull 163] Fix code highlight with safe mode

- [issue 142 pull 141] Fix parentheses and spaces in urls.
- [issue 88 issue 95 pull 145] Fix code blocks in code blocks with syntax highlighting.
- [issue 113 issue 127 via pull 144] Fix fenced-code-blocks html and code output.
- [pull 133] Unify the -/= and style headers and fix TOC order
- [pull 146] tag-friendly extra to require that atx headers have a space after

- [issue 135] Fix fenced code blocks odd rendering.
- [pull 138] specify shell in Makefile
- [pull 130] break-on-newline extra
- [pull 140] Allow html-classes for img
- [pull 122] Allow parentheses in urls

- ["nofollow" extra, issue 74, pull 104] Add `rel="nofollow"` support
(mostly by https://github.com/cdman):

$ echo '[link](http://example)' | markdown2 -x nofollow
<p><a rel="nofollow" href="http://example">link</a></p>

Limitation: This *can* add a duplicate 'rel' attribute to raw HTML links
in the input.