Immersive mode

This adds the ability to toggle statusbar / navbar via quicksettings (former expanded desktop), but
using the new 4.4 APIs that allow a swipe-up, swipe-down gesture, to restore bars.

Credits to CM project for the implementation
http://review.cyanogenmod.org/#/c/53468/

Drawables by Arz Bhatia

Change-Id: I1f694d87f0364aed7b6951714ea2bfbfd8555064

Credits to ParanoidAndroid for the cleaner implementation
https://gerrit.paranoidandroid.co/#/c/235/

Change-Id: Ie8ef8cf5c66a33f9991a9bcf2ea088b82163c86d