Markdown2

- [Issue 30] Fix a possible XSS via JavaScript injection in a carefully
crafted image reference (usage of double-quotes in the URL).

- [Issue 29] Fix security hole in the md5-hashing scheme for handling HTML
chunks during processing.
- [Issue 27] Fix problem with underscores in footnotes content (with
"footnotes" extra).

- [Issue 24] Set really long sentinel for max-length of link text to avoid
problems with reasonably long ones.
- [Issue 26] Complete the fix for this issue. Before this change the
randomized obscuring of 'mailto:' link letters would sometimes result
in emails with underscores getting misinterpreted as for italics.

- [Issue 26] Fix bug where email auto linking wouldn't work for emails with
underscores. E.g. `Mail me: <foo_barexample.com>` wouldn't work.
- Update MANIFEST.in to ensure bin/markdown2 gets included in sdist.
- [Issue 23] Add support for passing options to pygments for the "code-color"
extra. For example:

>>> markdown("...", extras={'code-color': {"noclasses": True}})

This `formatter_opts` dict is passed to the pygments HtmlCodeFormatter.
Patch from 'svetlyak.40wt'.
- [Issue 21] Escape naked '>' characters, as is already done for '&' and '<'
characters. Note that other markdown implementations (both Perl and PHP) do
*not* do this. This results in differing output with two 3rd-party tests:
"php-markdown-cases/Backslash escapes.text" and "markdowntest-cases/Amps
and angle encoding.tags".
- "link-patterns" extra: Add support for the href replacement being a
callable, e.g.:

>>> link_patterns = [
... (re.compile("PEP\s+(\d+)", re.I),
... lambda m: "http://www.python.org/dev/peps/pep-%04d/" % int(m.group(1))),
... ]
>>> markdown2.markdown("Here is PEP 42.", extras=["link-patterns"],
... link_patterns=link_patterns)
u'<p>Here is <a href="http://www.python.org/dev/peps/pep-0042/">PEP 42</a>.</p>\n'

- Fix syntax_color test for the latest Pygments.
- [Issue 20] Can't assume that `sys.argv` is defined at top-level code --
e.g. when used at a PostreSQL stored procedure. Fix that.

- Fix sys.path manipulation in setup.py so `easy_install markdown2-*.tar.gz`
works. (Henry Precheur pointed out the problem.)
- "bin/markdown2" is now a stub runner script rather than a symlink to
"lib/markdown2.py". The symlink was a problem for sdist: tar makes it a
copy.
- Added 'xml' extra: passes *one-liner* XML processing instructions and
namespaced XML tags without wrapping in a `<p>` -- i.e. treats them as a HTML
block tag.