Revert "[ActivityManager] Improve task order of getRunningTasks."

This reverts commit 770bc821bacd3a4b335b6656965542af55fc494d.
kill app long press back
Add global reboot option

Add global reboot option when long press power key and confirmation dialog
when user chooses to reboot device.

Conflicts:
	core/res/res/values/strings.xml
Add clear all recents action to recents panel

Change-Id: I2243ebc83abc483e78b112900a653d7e61edc5ba

Conflicts:
	packages/SystemUI/res/values/strings.xml