WebRTC support helpers

Shared signalling helpers and sample/app adapters layered on top of the core WebRTC module.

webrtcsupport

Shared signalling helpers and sample/app adapters layered on top of the core WebRTC module.

Name	Description
`WebSocketSignaller`	SignallingInterface implementation using plain JSON over WebSocket.
`SympleSignaller`	SignallingInterface implementation using the Symple call protocol.
`SympleServerSignaller`	Server-side Symple signaller for virtual peers and embedded apps.