Navigation Bar: Toggle last app on recents button long press

Long pressing the recent apps button on the navigation bar will launch the last open app.
Cherry-picked from https://github.com/omnirom/android_frameworks_base/commit/6fb093b3311942beae7f51e23abbf18aa8c99bf8

Change-Id: I1e6d6255494991b440f3cf5854a7edad7fee2c1b

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/BaseStatusBar.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java
PS2: Removed unwanted imports and tabs.

Change-Id: I1536d32cdc07ddd442c63d40d1c467499a8a505e