camera: Add support for ZSL on new Samsung devices

 * The camera driver on new Samsung devices requires that we send a
   magic command to the hardware in order to get ZSL behavior with
   continuous preview. On previous devices, this worked as long as the
   "cam_mode" parameter was zero (instead of null) and "camera-mode" is
   set to 1. On JF, we need to do all of these things.
 * The command we need to send is 1508, but I do not know what this
   value actually corresponds to. It was discovered by reverse
   engineering.

Change-Id: I6bccc9cd228784045eef81719892121749af4fa5

Conflicts:
	res/values/config.xml
	src/com/android/camera/CameraManager.java
	src/com/android/camera/PhotoModule.java
	src/com/android/camera/util/CameraUtil.java
Camera: Allow a device to request the focus modes at build time

By default, if a HAL supports touch-to-focus, mode selection is
disabled. Make that an option for devices where manual modes
work better without TTF (Macro, for instance)

Change-Id: Id47fba2a9d156b157440485a0fa516871076d9f9