Custom clear recents button (1/2)
    - Option to show/hide
    - Option to choose which corner to place (top left, top right, bottom left, bottom right)

Thanks omnirom team
Original commit: https://github.com/omnirom/android_frameworks_base/commit/dc9ddf62c4a0b1710ad3ce4bdf19ce5dcf63094c

Change-Id: I9c15fee94de38cd94a8d685b76a43af58c48bd5e

Conflicts:
	core/java/android/provider/Settings.java
	packages/SystemUI/src/com/android/systemui/recent/RecentsHorizontalScrollView.java
	packages/SystemUI/src/com/android/systemui/recent/RecentsPanelView.java
	packages/SystemUI/src/com/android/systemui/recent/RecentsVerticalScrollView.java