add connectionProvider option to createServer

[rom1504]

to support non tcp use cases

[redbrain]

WebRTC should be a possible setting for this option, as it's the standard for inter-browser communication, a likely non-TCP use case.

[rom1504]

Yes this could be part of an example (using https://github.com/feross/simple-peer ) However nmp itself should not depend on webrtc and instead simply expose a connectionProvider option