Upgrade to Bootstrap 2

Also reworked the profile list to use Bootstrap thumbnails (with some custom tweaks to remove the border/shadows) so they line up a bit better.

I've moved the Bootstrap CSS into the `media` directory as the Bootstrap docs site no longer seems to encourage hotlinking it. I tried adding the responsive stylesheet, but it screwed things up due to the custom width set on `.container`. Probably not too trick to fix.