Reenable telemetry.
Rework transition to closed to match other transitions.

Fixes #178
Teach JsepSession to reject m-lines when necessary.
Negotiation failure signaling_unittests.

Also, add a check to jsep_session_unittest.
Better checking of direction attributes in answer.

Detects issue #221
Answerer pays better attention to offer direction.

Fixes #221, as well as a similar bug where we would pair up local
streams with sendonly m-lines in the remote description.
Merge pull request #225 from docfaraday/answerer_direction_fix

Answerer direction fix
Create MediaPipelineReceive correctly for video.

Fixes #226
Merge pull request #227 from docfaraday/fix_mediapipelinereceive_create

Create MediaPipelineReceive correctly for video.
Fix ICE component count bug in mochitest.

Code was counting number of succeeded candidate pairs in the stats, but
it is easy to have multiple succeeded pairs per component. Now counts
selected pairs. Also, changed some naming.
Disable unneeded ICE components, and fix a duplicate candidate bug.

When answerer between SetRemote and SetLocal, we were buffering remote
candidates both in the remote SDP, and a buffer in PCMedia. When
offer/answer concluded, these candidates were added twice, which was
confusing the mochitests.
Merge pull request #218 from docfaraday/handle_no_codecs

Handle no codecs
Merge pull request #228 from docfaraday/disable_unneeded_ice_components

Disable unneeded ice components
Moving to binary fingerprints
Review comments
Merge pull request #87 from martinthomson/binary_fingerprint

Moving to binary fingerprints
Re-enable ice_unittest
Prevent duplicate pairing of host candidates.

Fixes issue #230. Also adds some helpful logging.
Check protocol in answer.
Use the right protocol when forming answer m-lines.

Fixes issue #229. Fixes issue #157. Also, got rid of default params on
Sdp::AddMediaSection, since it is virtual, and we aren't using them
anymore.