SystemUI: StayAwake Toggle

* Icon is in the works (Interim icon is AOKP cog)

Instead of overcomplicating toggle, onLongClick simply takes the user to
Settings$DisplaySettingsActivity instead. onClick (on) sets screen timeout to
int MAX_VALUE(approx 24 days), and restores user value onClick (off).

Change-Id: Ifd2051b2a6e8235160713cad3b4385dbb6d66b8f
Signed-off-by: bmc08gt <bmc08gt.teamb00sted@gmail.com>

Conflicts:
	packages/SystemUI/res/values/strings.xml
Pie : Check operator

Change-Id: I98f02e6361c51534b7cbb0d26a863b295ca8d4b6