Revert "always expose native battery percentage when unplugged"

This reverts commit fe99dde052249966ab7b409e53be24c338283cad.
Status bar brightness control improvements

- Fix status bar brightness control when on secure lock screen.
- Prevent brightness changes after notifications panel has been opened.
- Don't adjust brightness for swipes <45° from vertical.
- Stop using a VelocityTracker

reference:
https://github.com/CyanogenMod/android_frameworks_base/commit/71c97740b5404b3c0be89454e55a69c1ca8655ec
https://github.com/CyanogenMod/android_frameworks_base/commit/212c63a250b81676a89f9de145cf4f1b378b43fb
Kill app long press back: use a separate class