SystemUI : Port forward statusbar brightness control

Brings back the status bar brightness control from cm-10.2/cm-11

Change-Id: Icc04e7da3286e9925f8b90528c1e022b33d33e9d
SystemUI: Use material delete icon

Change-Id: I11df5713486672e4f5c4784e6f94a893cf36b4dd