Themes: Allow clearing the wallpaper and ls wallpaper

By providing an empty string for the MODS_LAUNCHER and
MODS_LOCKSCREEN components, the theme service will clear out any
existing wallpaper the user had set.  This provides the same
functionality as if the user was picking "No wallpaper" from the
picker.

Change-Id: I0c349ad4afa2bcef2c302105315709786510c0aa
Themes: setUserRequired(false) when updating audibles

This prevents the following exception
F/Environment(18007): Path requests must specify a user by using UserEnvironment
F/Environment(18007): java.lang.Throwable
F/Environment(18007):   at android.os.Environment.throwIfUserRequired(Environment.java:787)

Change-Id: Ic6ac7537079ed27912c40683c877e05992b708e9
Fix camera usage tracking.

When a Camera object is finalized, it notifies the torch service that
it's no longer using the camera. This call used to not check whether the
caller actually is still using the camera and called release() before,
so depending on timing of the finalizer, it could happen that e.g. the
camera app released the camera user record of the torch app, leading to
the torch usage not being detected on next usage of the camera app.

Fix that by checking whether the caller of onCameraClosed() actually
owned the camera prior to releasing the record.
Also fix synchronization between accesses.

Change-Id: Ic01cbc3c89ab8d855e4613bfa1b2f548de919b73
Fix ressource leak in getFileCrC

Change-Id: If8a63fa355664d360aab6ecba92c82cd56b745b8
PowerManager : Make proximity check opt-in

Change-Id: I7cf64a82530da2e655018e43683ba7a5584d54f8