Bug 930696 - Upgrade to bootstrap 3.0, modernize look of dashboard;r=davehunt

More room for content now, less whitespace / chrome. Still pretty.
Bug 928115 - Actually support higher fps modes in get-metric-for-build;r=davehunt

Not quite yet working for the dashboard yet, but I thought it would be good to
get something basic going so we can start comparing results, etc.