ClearAllRecents: force recents activity to finish when idle
When another app is launched from navbar ring or quick settings (or
whatever other way), recents activity will end up in a paused state
which prevents recents key from working correctly next time it's
pressed. We force finish of recents activity in case it was not resumed
in specified amount of time (500ms).
This also fixes stuck clear all navbar key - it will go away when finish
runnable is fired
ClearAllRecents: optimizations
Recents panel: Clear all in navigation bar / pie
Fixed icon coloring in pie
Set clear all icon alpha to better match AOSP icons
ClearAllRecents: fixed broken feature on Android 4.1

Clear all in navigation bar / pie feature must be removed because
com.android.systemui.recent.RecentsActivity class does not exist on SDK
16.