HOVER: Option to exclude topmost app [1/2]

Originally taken from Tigger2014:
https://github.com/Tigger2014/android_frameworks_base-1/commit/5af0e1c84e86e9b4e6947163aaf58e9ab541079d

Change-Id: I6da9027af4c7bc74945a06b97b876f94cf817844

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/notification/Hover.java

 Author:    Schubi <schubi@erlangen.ccc.de>
Hover notification timeout [1/2]

Allow user to set how much time the hover notification will stay visisible without touch the screen

Change-Id: I5847adb3f33522d9d78867685f9867477542c37e

Conflicts:

	core/java/android/provider/Settings.java