Newest pull request / Second revision cleanup of ORTC API draft

I've made a bunch of cleanups to the API. This should simplify the API 
and clean up some issues that were present. Still more to do and likely 
contains some errata to fix but I think this is a good leap point for 
the next round of feedback. This is the API I would like to present in 
Vancouver.

https://rawgithub.com/robin-raymond/ortc/master/ortc.html
https://github.com/openpeer/ortc/pull/16


Changes to RTCConnection:

  * added attribute socket
  * added attribute state
  *

    added attribute role

  *

    removed method getLocalSocket

  *

    removed method setLocalCandidate

  *

    renamed method setRemoteCandidate to addRemoteCandidate

  *

    renamed method update to gather

  *

    renamed method addStream to send

  *

    renamed method receiveTrack to receive

  *

    removed method addDtmfHandler

  *

    renamed method getSendingStreams to sendingStreams

  *

    renamed method getReceivingStream to receivingStreams

  *

    renamed method tracks to sendingTracks

  *

    removed method track

  *

    added method receivingTracks

  *

    removed event onconnected

  *

    removed event ondisconnected

  *

    added event onstatechanged

  *

    removed event onaddstream

  *

    removed event onddtmfhandler

  *

    added event onnetworkchanged

Removed "autostart" boolean flag to send stream since now can construct 
"RTCTrack" object before calling send thus parameters can be tweaked 
before they become active.

Made DTMFStreamTrack object into a constructible derived class of RTCTrack

Added RTCDataChannel object

Added RTCStream object

By no means perfect but a lot clean up has happened to make the 
interfaces clearer!