Changes

tests: add trau2rtp_gen program

This test program converts TRAU-16k or TRAU-8k frames into RTP payloads,
both represented in hex.  (Hex representation of RTP payloads follows
TW-TS-005 spec; hex representation of TRAU frames is ad hoc.)  It can
be used as a basis for unit tests, verifying that a given TRAU frame
input turns into corresponding RTP output, and it can also be used
(in conjuction with additional Themyscira utilities) to turn captured
TRAU frame streams into playable audio.

Change-Id: I3cc8502406e930317b680b0ace2fce479e495ccd