When a new SSRC is seen we start a Read loop for the packets. However if
we only see one packet this loop will just sit forever. If a user
doesn't send us enough packets to finish probing it will prevent any
subsequent streams from being probed.
Relates to #1345
Resolves#478. Adds minimal JavaScript/WASM bindings. This makes it
possible to compile core parts of pions/webrtc to WASM and run it in the
browser. Only data channels are supported for now and there is
limited/no support for certificates and credentials.