ASACORE-953 - Add About Client with Announce processing

ASACORE-953 - Add About Client with Announce processing and handler
              registration
              Fix AJ_AboutHandleAnnounce() to handle NULL arguments.

Change-Id: I3a839d0f589c274b947d5258a60759e5ec6f184f
Signed-off-by: Eyal Ilsar <eyali@qce.qualcomm.com>
Merge "ASACORE-953 - Add About Client with Announce processing" into RB14.12