Camera: Extend few data structures for QCom features.

Add message type for STATS_DATA and also the commands
which the application sends to start/stop histogram.
Also add few members to the face structure to extend
the face detection feature.

Change-Id: I3cc1c99ce40b58a029b1e048e6f84265833ac372
Camera: Adds meta data message and commands

- This change adds support for meta
  data type notification messages and
  commands.

Change-Id: I4d19254be90ac43a40e7d02d74a3c7c1a2bad336