TrafficMeterOmni: added option for auto-hiding on inactivity
Together with inactivity threshold
Recents panel: Clear all in navigation bar / pie
Revised by C3C0:
- squashed all commits into one
- minor changes regarding formatting
- major glitch fixed - details below

When recents key has no actions set (default for both - single and
long-press) and when user is in recents and long-presses the clear all
key, action is taken, recents screen is dismissed but it is immediately
reopened afterwards when user releases the key - this is because in the
meantime recents key was changed back to normal.
Solution: wait until user releases a key before changing it to normal

Revised by bgcngm:
- avoid usage of getIcons method from NavigationBarView class as it was
only implemented on Android 4.3
Clear all recents in navbar: fixed rotation change related issues
When screen is rotated, recents panel and navbar are recreated which
triggers setRecentAll() method. Backup actions are thus replaced with
current CLEAR_ALL actions resulting in unfunctional recents key after
recents panel is dismissed.
Make sure we back up default actions only in case they are not CLEAR_ALL
actions
Implemented Notification LED control
Allows notification LED control on per-app basis.
This is a premium feature.

Cherry-picked and backported from KitKat branch