improved the client check so now it uses sip.js and bbb_webrtc_bridge_sip.js...

improved the client check so now it uses sip.js and bbb_webrtc_bridge_sip.js from the bigbluebutton-client, so it's going to be easier to maintain; included some new callbacks on bigbluebutton-client related to the websockets; just after the webrtc test, the connection is closed