WallpaperCropper: load wallpapers in the background

Change-Id: I134d94a85f25bf5db4c15fa9a89265c53e5b0c1d
Signed-off-by: Roman Birg <roman@cyngn.com>
Themes: Add URI for querying previews of applied components.

Change-Id: I97417901f3b03fc82df5a823970991ddd8092df2
Themes: Add method to "apply all" a theme

Change-Id: Ic8feaeade6c52707e6b5b17921b1b577b94ec8cf
add framework torch service

Change-Id: I0c7a055b33fdebe697f23d207b20408e06eb74a8
Signed-off-by: Roman Birg <roman@cyngn.com>
Fully fix interaction between torch and camera usage.

For doing this, two things are necessary:
- The torch shutdown needs to be synchronous, so that the torch app has
  a chance to release the camera before the camera app tries to use it.
- The torch service needs to track camera usage, so that it can notify
  the torch app if a camera is busy.

Change-Id: I521091d255ff4c251d97a0e8d65c9d2a80b9dae4