These FEC codes perform better for bursty (consecutive loss) than the existing set (which were designed for random loss). Updates to the unittests and test_fec accordingly. Review URL: https://webrtc-codereview.appspot.com/581005 git-svn-id: http://webrtc.googlecode.com/svn/trunk@2369 4adac7df-926f-26a2-2b94-8c16560cd09d