migrated the repo browser to bootstrap

The SASS (rails) compatible version of bootstrap wasn't defining
classes properly, and this could be seen when I tried to do the
breadcrumbs. To fix it, I just installed the regular distribution of bootstrap
and removed the gem from the gemfile. I've also installed an icon set for use
specifically in the repo browser (but can be used on ther est of the site).
The last commit to the branch resulted in destructive changes to the gemfile,
so I added rugged & coderay back to that.

The repo browser now (mostly) uses the bootstrap style for an attractive look.