Camera: port additional settings from jellybean 4.1 (Round 2)

- add touch-to-focus timeout duration settings
- add volume button zoom controls to camera and camcorder
  (Panorama does not support zooming)

Change-Id: Ib2c2c152a52b2616dd0da6f071f572d34fe64065
Camera: properly detect multiple cameras when using the camcorder

Currently, the option to switch between front and rear cameras is
available whether or not the device has multiple cameras. It does
work correctly when in camera (still) mode , the bug only happens
in the video camera.

Change-Id: I66d1a01ff496ed03544049bd1d03881fbef3a07f