Mesos documentation now rendered on website

[Dave Lester <da...@berkeley.edu>]

Hi All,

I'm psyched that we're now rendering the Mesos documentation (stored in the
/docs folder of your download) on the Mesos website:
http://mesos.apache.org/documentation/latest/

This change should help with SEO for the website, also make it a much more
pleasant experience to browse the docs rather than having to go off-site to
Github to read them.

There's definitely room for improvement with regard to styling, and keeping
the overall docs up-to-date. Feedback welcome; patches preferred!

Dave