Revert Active Display commits

Change-Id: I7056e2a7c7a6891b974cbcb423d226375f333ae3
[WIP] Multi-window

This is a big work in progress, which currently has some bugs,
but begins to look okay.

You can already multitask a little bit, by using the
app switcher and long-pressing an icon, then select "Add to
Split View".
Last window touched gets the key focus.

Still are some issues with rotation handling - touch an app
after rotation to make it relayout.

Enjoy :)

Patch Set 19

Change-Id: I4a03a84539fd3ac1273f0d3503fe8fafcd16be26

Conflicts:
	core/java/android/app/Activity.java
	core/java/android/app/IActivityManager.java
	core/java/android/content/Intent.java
	core/java/android/view/IWindowManager.aidl
	packages/SystemUI/res/values/custom_strings.xml
	packages/SystemUI/src/com/android/systemui/recent/RecentsPanelView.java
	services/java/com/android/server/am/ActivityStack.java
try to fix Halo + MultiWindow

Change-Id: I9e6d5468e5a628532aa31079f44f4bf1733a6afa