Response for close command

If `DELETE /session/{session_id}/window_handle` removes the last window
the remote end is supposed to close the session. However there is no
response to indicate to the local end that this happened. Adding such a
response would allow the local to take whatever steps are required to
indicate that there is no longer a session, rather than retaining stale
session information.

Received on Wednesday, 11 February 2015 10:21:01 UTC