Better fix for FM-530. Instead of relying on the Play.PublishNotify event (which won't get dispatched for streams that are already published) to enter the playing state, check the bufferTime value and immediately exit buffering mode if it's zero. In that case (which seems to only happen with live), the Play.Start event is the last one we'll get, so we can't rely on a Buffer.Full event (which makes sense if bufferTime is zero).
