Status bar brightness control from CM10 (1/2)

Change-Id: Ida526bf19e56d549f7cc75c47466e6953295d888

Conflicts:

	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java
Revert "Revert "Halo: Add master switch to disable Halo (1/2)""

This reverts commit 4e787e82654e794a445ad339e00b39c6d5e2b76d.