pjsip: don't put bandwidth information on the SDP for audio streams

Ignore-this: 4654f542f8ef5a971ef6a8a0f6cdbc24

darcs-hash:20140919172337-56b4d-2c43df06976f48eb25121891e6333a9b57f1e166
Add setting for limitting bitrate for video calls

Ignore-this: a1dd590f24b55dc32184444a14753d53

darcs-hash:20140922074448-56b4d-220474a02c7b98df2b59514c9fe14ed949331629
pjsip: adjust clock to detected remote framerate

Ignore-this: 4a744354bf7870985eee78a08cae54e

darcs-hash:20140922123619-56b4d-f7436ce738eefde0305cc0b2e37c894ed38fe97d