Now adopting an RTCP client so that the RTP stream from the RTSP server can be maintained past 1 minute.
This change involved some refactor.
The rtcp.NewClient signature has been simplified. There is now a default send interval and name for use
in the source description in the receiver reports. These can be customised if required with the new
SetSendInterval and SetName funcs. The rtcp.NewClient signature now takes an rtp.Client, so that it
can get information from the RTP stream, like most recent sequence number. As a result of this requirement
the rtp package parse file has been extended with some functions for parsing out the sequence number and
ssrc from RTP packets and the RTP client provides getters for these things.
Finished writing the client_test.go file and through the process fixed some bugs in the client. Also increased usability by providing a Stop() method
so that the send and recv routines, and also the connection can be terminated. Also created a sender report struct in rtcp.go - this helped with
testing.