Add a quick SELinux mode toggle

There's no way to make it persistent, by design. This is purposefully
undocumented and meant to test policies at this stage.

Change-Id: Ic79ed773b199b68fee15f94acd2107a5ad20dc25

Conflicts:
	src/com/android/settings/DeviceInfoSettings.java
Option to disable wallpaper service

Change-Id: Ia80ae699979a69cdf3497955967df59658cbe5bf

Conflicts:
	res/values/cm_strings.xml
	res/xml/performance_settings.xml
	src/com/android/settings/cyanogenmod/PerformanceSettings.java