Notification Shortcuts [1/2]

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 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: If73289fcbc9b7ee3fbb3d0c10c8d4c42511c088b