FWB: Hover customizations from Liquid rom (1/2)

Options to exclude non-clearable and low priority notifications
Option to only show up in Fullscreen-Mode
Option to exclude topmost app
        Originally taken from Tigger2014:
        Tigger2014/android_frameworks_base-1@5af0e1c

PS3: fix invert value

Change-Id: I07753c99a6ce1c1f88ee26334879c08cae90137f