Add video bandwidth tests that measure rtt, bandwidth estimation and time to rampup over a 40 seconds loopback call.

Add stats.js with utilities.
Add more utilities to call.js to filter FEC and set a max bitrate.
Addressing holmer comments.
Merge pull request #124 from GoogleChrome/holmer-video-bandwidth-test

Add video bandwidth tests that measure rtt, bwe and rampup time.