framework: lunar string substring 2,length

Change-Id: I8c172bce4b159518f601e8e393cac86e2664d436
Low-end devices need help!

-> Check for wakelocks faster
-> More granular hidden apps selection
-> Kill hidden and service_b apps at higher lmk
-> Rearrange OOM values [similar to SuperCharger! But not exact]

Change-Id: If6163a8c15b8c3ec622a44124609be21b4359e36