Add Samsung MultiWindow support

From WakiWaki on 2016/08/22 18:29:16 +0000

Even though AOSP multi window is coming in android 7.0 millions of devices won’t ever get that version. I would like to suggest support for Samsung multi window support. It would be very helpful in situations where you look at other apps when creating an alarm.
More info:
http://developer.samsung.com/technical-doc/view.do?v=T000000144L

Copied from original feature request: http://urbandroid.uservoice.com/forums/264867-sleep-as-android/suggestions/15748543-add-samsung-multiwindow-support