Hg fileserver

created a mercurial file server like the git file server but for those that use hg.

Needs to additional testing for sure. I was able to run some high states with this, but I havn't exercised the code completely.

I will also be working on adding bookmark support (currently only uses branches and tags)

It requires [hglib](http://mercurial.selenic.com/wiki/PythonHglib).