Issue 224: RTCIceGatherPolicy harmonization with WebRTC and Issue 244: Changing iceServers on an RTCIceGatherer

Peter St. Andre has pointed out a discrepancy between RTCIceGatherPolicy in ORTC and RTCIceTransportPolicy in WebRTC 1.0.

ORTC has:

enum RTCIceGatherPolicy {
"all",
"nohost",
"relay"
};

WebRTC has:

enum RTCIceTransportPolicy {
"none",
"relay",
"all"
};

Consistency might be desirable with respect to "none" vs. "nohost".
[BA] The discrepancy required a work-around in adapter.js since RTCIceTransportPolicy.none has no equivalent in ORTC, so it seems like something worth fixing.

So why can't we just add RTCIceGatherPolicy.none?

The problem is that an  RTCIceGatherer constructed with RTCIceGatherOptions.gatherpolicy.none could never gather any candidates and would therefore be useless.

This is because the RTCIceGatherer has no gather() method that could be used to reset the gatherPolicy to another value.  Another implication of this is that it is not possible to reset iceGatherer. iceServers (e.g. to add a STURN or TURN server) - you have to construct another RTCIceGatherer with the new iceServers value.

It would therefore appear that issues 224 and 244 are related (and need to be solved together).