Add CrossOriginConnectEvent and CrossOriginServiceWorkerClient objects.

This change adds the appropriate prototypes so that the object passed to
the 'crossoriginconnect' event handler has a 'client' field that
contains a proper CrossOriginServiceWorkerClient object to match the spec.

This client object is not yet set as the source for 'crossoriginmessage'
events.
Pass CrossOriginServiceWorkerClient to 'crossoriginmessage' handler.

Set the source of the 'crossoriginmessage' event (which is still not a
real MessageEvent object) to the same CrossOriginServiceWorkerClient that
is used in the 'crossoriginconnect' event. The origin associated with
the client is not yet populated correctly.
Merge pull request #5 from reillyeon/gh-pages

Add CrossOriginConnectEvent and CrossOriginServiceWorkerClient objects.