Add PowerManager integration for button and keyboard backlight.

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

Change-Id: I550cccafc0a8f90d6347de9261adb26b75955cc4
Merge "Add PowerManager integration for button and keyboard backlight." into cm-10.2
Telephony: Add RIL request and event for OMH support

Change-Id: I8f68d6d9e1e188a2c2295a814376dccaaad5ec24

Conflicts:
	telephony/java/com/android/internal/telephony/DctConstants.java
	telephony/java/com/android/internal/telephony/RILConstants.java