Wiring up RTP Transport.

- Add support for loading config.xml values pertinent to
ImsPhoneCallTracker on phone initialiation.
- Add support for new shell command "d2d send -t type -v value"; this
lets us test sending D2D comms messages.
- More logging!

Test: Performed test of new adb shell command and verified that logs
indicate proper passthrough of messages.
Test: Added unit tests to verify that the D2D communicator will be set up
in a TelephonyConnection when it's an IMS connection and D2D comms is
enabled.
Bug: 163085177

Change-Id: I042e7da030e6dd41d2c20f095416185a14194213
5 files changed