RecordRTC, MediaStreamRecorder and RTCMultiConnection-v1.6

Now, both RecordRTC and MediaStreamRecorder can record audio+video in
single WebM using Firefox's MediaRecorder implementation.

Demo:
https://www.webrtc-experiment.com/RecordRTC/AudioVideo-on-Firefox.html

"session.join" and "autoTranslateText" added in v1.6; also, issue #152
is fixed.

http://www.rtcmulticonnection.org/changes-log/#v1.6