removes encryption and signing. Relays on webrtc DTS. Keep authenticatio...


webRTC implements DTLS http://chimera.labs.oreilly.com/books/1230000000545/ch18.html 
which is an adaptation of TLS for datagram oriented transport layers. 

TLS provided *authenticated encryption* for the channel, and replay attack protections, therefore 
there is no need to sign or encrypt messages between the peers in our webRTC network adaptor. 

Yet, this PR keeps the (new) authentication checks for maxPeers and pubkeyRing.  The first one prevents more that N parties (totalCopayers) to join a session. pubkeyring checks, using `allowedCopayerIds `, prevent outsiders to join a wallet session, *once the publickeyring is complete.