Pass creation time in Call interface so that we can uniquely identify calls in call log

Change-Id: Id235a1fa3b639ad684b4f69d676e55925886d905
Handle CALL_IS_WAITING MO notification.

Make that piece of information available to InCallUI so that it can
display it.

Change-Id: Id429824d3af85cf16290b8286b87903c9dc02655