Implement packet loss calculations in Receiver Reports

In order to support servers that have implemented the
dynamic bandwidth adaptation feature are these
fields added to the receiver report:
      -Fraction
      -Cumulative number of packet loss

The calculation is based on RFC 3550, section A.3.

Change-Id: I9500ee20b2aa393c495bfc79289b26abd1267289
Merge "Implement packet loss calculations in Receiver Reports" into jb42