keyboard: adding functional alt/shift lights

This is useful for devices that has QWERTY keyboard
and leds for the Alt/Shift (Fn/Caps) keys, like
htc doubleshot.

Depends on libhardware patch for the light ids:
http://review.cyanogenmod.org/34902

Change-Id: I66ebc2d881438f5b51db77eaa885421e65a7da0d
Add PowerManager integration for button and keyboard backlight.

Allows setting button and keyboard backlight brightness as well as
button timeout.

Change-Id: I550cccafc0a8f90d6347de9261adb26b75955cc4

Conflicts:
	core/java/android/provider/Settings.java
	services/java/com/android/server/power/PowerManagerService.java

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