Updated to WebRTC 3.52

Added necessary changes to use WebRTC 3.52.
Reformatted code in WebrtcHandler.
Fixed WebRTC teardown issues

Added updated libjingle binary that fixes WebRTC VideoSource
teardown crashes.
Changed WebrtcHandler to "reset" itself after receiving a BYE
message and tearing down its existing PeerConnection and
VideoSource. This allows the client's background service to keep
the socket connection open and renegotiate the WebRTC connection
whenever the client resumes the AppRTC activity.