Change promises in transport provider.
Rate limit transport to avoid filling WebRTC buffer.
Still needs to queue messages internally if two "send" calls
to transport are made.
Queue messages by tag.
Merge branch 'master' into paul-transport
allow promise-based providers
test for promise based provider
add interface for core.udpsocket
promise errors flow through as per #51. Unit test needed.
unit test for promise rejection. close #51.
Merge pull request #52 from UWNetworksLab/yangoon-core.udpsocket

add interface for core.udpsocket
v0.3.2