Parse/Render RestructuredText/Markdown/Textile files as HTML (BB-1080)

Hi,

Currently, Sphinx appears to be gaining traction within the Python world as the standard for documentation, particularly in Django projects.

Github appears to correctly parse .rst files in repositories, and render them as HTML. E.g.:

https://github.com/dcramer/django-sentry/blob/master/docs/index.rst

It seems a bit embarrassing that BitBucket, which is based off Mercurial and meant to be Python-oriented, can't even get this right. E.g.:

http://bitbucket.org/ned/coveragepy/src/ad548b94dda6/doc/index.rst

Github has better Python support that us? That's so not cool...lol. Would be awesome if this could be fixed.

Cheers,
Victor