Merge pull request #80 from nils-ohlmeier/multistream

added origin tests
Create an answer with apparently the right number of m-lines. Would be nice if there were tests for it
SDP errors now report line numbers
Start testing serialization.
Checkpoint on SetLocal(Answer)
Merge pull request #81 from adamroach/sdp

SDP errors now report line numbers
Merge pull request #82 from docfaraday/multistream_unit_tests

Start testing serialization.
Adding a=group support
Merge pull request #83 from martinthomson/sdpwrap

Adding a=group support
More line numbery goodness
And put the line number in the error log, too
Start of actually emitting the tracks
Merge pull request #84 from adamroach/sdp

More line numbery goodness
Merge pull request #86 from ekr/MS_create_answer1

Ms create answer1
Short circuit properly, and remove some outdated comments.
fmtp support, make some loops safer, and add some useful asserts to the
unit test.
Merge pull request #88 from docfaraday/multistream_unit_tests

Multistream unit tests
Export a trivial description of the negotiated track pairs
Merge pull request #89 from ekr/MS_more_call_setup

Export a trivial description of the negotiated track pairs
First test with the full JSEP interaction