Short circuit properly, and remove some outdated comments.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
Merge pull request #90 from ekr/MS_full_call_setup

First test with the full JSEP interaction
Adding offerToReceiveX