Don't override SDP connection line when removing streams

Ignore-this: 3299f27bf76dd54788dbe4f1de893016

darcs-hash:20141118102324-56b4d-869fecce2264d2196bb81288b782c58b5a0e2375
Use same SDP connection line for rejected streams

Ignore-this: 279c9adc7bb3e17d47773c8676d9155b

darcs-hash:20141118104124-56b4d-89f86732b3897963d92dec80156775393deb15a2
Fix setting SDP connection line when accepting a proposal

Ignore-this: 6a28a442fde30c11be01efdc8caef3ac

darcs-hash:20141118104145-56b4d-d5910838d2ec40df10b45465ccb5e90f756ebccb