Tuna : Add display gamma calibration

Allow user to calibrate display gamma.

PS 3: Cleanup code.
      Better gamma values
      Needs: http://review.cyanogenmod.org/48901

PS 4: Restore original commit message

PS 5: Restore old ordering

PS 7: Restore original names of variables & unify both files

Change-Id: I2aa1d746ec6c8372f80e022b786078c5ded68612
Revert "Turn off BLE, GATT, and SMP of Bluetooth stack"

This reverts commit 55272b3a4e917143012a77d937ca2670ec26e0fb.

Both Maguro and Toro do support BLE but for some reasons Google has disabled it
from factory images of 4.3

Change-Id: I7402484a7bc4ebc99b4f6efea1511a57f88991b0