Settings: privacy Guard enhance app logic

This commit changes the following

- do not show apps signed with the plaform certificate at all
  (like settings, systemUI, android system etc)
  IMO the user should trust the android signed apps to be save and this will
  prevent weird behaviours user can get when they activate it on this packages
  all other system apps (like calculator, browser) and all which are not signed with
  android key are not effected.

- to go inline with AOSP disable the checkbox in detail app screen
  for built in apps

cheers

SlimRoms

Change-Id: I12b5522f6e58047173778381fb7290bb1c71bab3

Conflicts:
	res/values/cm_strings.xml
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