SIP telephony: integrate with new RTP stack and other fixes.

+ Add getAudioGroup() and getAudioStream() to SipAudioCall.
+ Fix sendDtmf()
+ Fix NPE in Flog
+ Fix holding call callback
+ Print entire stack for exceptions thrown in SipSessionListener

Change-Id: I32dd22af0b89695973dd6d7c3694eea4aa905dd1
6 files changed