fb: add back notification shortcuts feature + common slim classes

beside our unique slim feature this patch adds

- all system shortcut icons we need for this and other stuff in future
- basice slim helper and constants classes we need later as well
- device utils helper
- preparation for navbar navring and other shortcut features
- and of course our notification shortcuts feature

compared to 4.3 some fixes were added + adapting to 4.4

xxhdpi icons thanks to kroz again

Change-Id: Ie552480007bde649352c699c8ff9ac10e79ed069

Conflicts:
	core/java/com/android/internal/util/slim/DeviceUtils.java