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

Originally taken from Tigger2014:
Tigger2014/android_frameworks_base-1@5af0e1c

Conflicts:
	core/java/android/provider/Settings.java

(cherry picked from commit 1f899779cb4d20ead601544d95af01a437610b6e)

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/notification/Hover.java
Merge pull request #47 from Basti1337/patch-11

Update cr_strings.xml
(cherry picked from commit 4c362ee4544189dc0421664b7d7047ec3951e438)