Add missing header string and fix build error

Conflicts:
	src/com/android/settings/DisplaySettings.java
Move HALO to a separate preference

Inspired by this: https://github.com/Root-Box/packages_apps_Settings/blob/868e5476f26de6d605b3e8ea708b3d77830fd39e/src/com/android/settings/paranoid/Halo.java

Conflicts:
	AndroidManifest.xml
	res/xml/display_settings.xml
	src/com/android/settings/DisplaySettings.java
	src/com/android/settings/Settings.java