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 uses bootstrap styles for a nicer consistent look.

I've also slightly modified the application template to get rid of the strange black box that was 3/4 overlaying the dark gradient of the navbar, and added some padding to give it an even gradient lookup.