Settings: Add PerformanceControl to settings

Change-Id: I259323366ca0aac8b8d334bc9629dec5acc9108a

Conflicts:
	Android.mk
	AndroidManifest.xml
	res/values/custom_strings.xml
	src/com/android/settings/Settings.java

Conflicts:
	Android.mk
	res/values/slim_strings.xml
	res/xml/settings_headers.xml
	src/com/android/settings/Settings.java