PowerManagerService: Implement setButtonBrightnessOverrideFromWindowManager method

Differs from Android 4.1 (and earlier) implementation in that the
overridden button light still turns off after BUTTON_ON_DURATION instead of
staying on until screen off.  However, button lights are annoying, and
really the purpose of this is to allow apps (e.g., Screen Filter) to
_disable_ the button lights altogether.

Conflicts:
	services/java/com/android/server/power/PowerManagerService.java

Change-Id: If0639dbe01134b72b05fee7f8cd9368dc9a71e4f

Keyboard light: Fix the physical keyboard not light when it's visiable.

Conflicts:
	core/java/android/os/IPowerManager.aidl
	core/java/android/os/PowerManager.java
	services/java/com/android/server/power/PowerManagerService.java
	tools/layoutlib/bridge/src/com/android/layoutlib/bridge/android/BridgePowerManager.java

Change-Id: I595afd3cb6b422a17ae0f6ec20aa51979db13810
Merge commit 'refs/changes/50/450/2' of https://review.carbonrom.org/CarbonDev/android_frameworks_base into kitkat