Revert "Revert "Revert "Halo: Add master switch to disable Halo (1/2)"""

This reverts commit 4475b36c07aed6324fe5f0996e9fe8d0b8a89256.
Revert "Status bar brightness control from CM10 (1/2)"

This reverts commit c1ce25a95a07dbb1e73673a95ca0101314781d77.