minui: Allow devices to blank/unblank using LCD backlight

* Some devices rely on the LCD backlight to blank/unblank the display,
  support them by allowing a custom LCD backlight path to be used.

Change-Id: I8406b4b55cd7a2afc4f8f8ba65de2c53b949489d
Merge "minui: Allow devices to blank/unblank using LCD backlight" into cm-10.2
recovery: Add a proper CleanSpec.mk

 * Clean all the stuff that conflicts with AOSP recovery.

Change-Id: I175329c446a014c451f4c0fc5a9a4472941afc10
recovery: Clean ALL the things

 * We need to clean everything, otherwise nasty things happen when
   switching to alternate recovery module.

Change-Id: I9ea88179f5329112c587b649328c1c83df0bd5d9
recovery: nandroid: implement preference for backup_format

ro.cwm.prefer.backup_format takes:
dup (dedupe)
tgz (tar + gzip)
(i.e. setprop ro.cwm.prefer.backup_format tgz)

-If nothing is specified or the above is not matched then tar is used.
-If the user specifies a default_backup_format then that is used.

Change-Id: I935d6cc732c5ef2b1d0d44f5459425e85702e710