This program (derived from mncc_test.py) is used to start MT calls
via the MNCC interface of OsmoMSC. Every calls RTP is connected
to the new 'rtpsource' process, which generates a realistic RTP
flow in terms of number of packets (20ms interval) and payload size.
Change-Id: I9e5d799aaeeff5188dc97061f0d6e1873d9bf653