DisplaySettings: Add hardware-framework support for tap-to-wake

Since we have tap-to-sleep globally, might as well support the
wake gesture as a standalone thing through the HAF. Place it in
"Display".

Conflicts:

	res/xml/display_settings.xml
	src/com/android/settings/DisplaySettings.java

Change-Id: I6facc2334ff9e80077581c54c428476594e91528