Make All Apps<-->Workspace transition smoother

- grouping workspace/all apps anims into one
animator set, prevents blip when one of them ends
early and its end anim handler does lots of work
mid-animation
- updating pivots for all apps zoom if layout
changes
- avoid running unnecessary animations on
workspace pages
- prevent unnecessary reloading of pages in
All Apps

Change-Id: I53a75f7c4c7d254057e2f8f4fd17711e8862256d
diff --git a/src/com/android/launcher2/PagedViewGridLayout.java b/src/com/android/launcher2/PagedViewGridLayout.java
index b1b6215..90bfe88 100644
--- a/src/com/android/launcher2/PagedViewGridLayout.java
+++ b/src/com/android/launcher2/PagedViewGridLayout.java
@@ -109,6 +109,7 @@
     @Override
     public void removeAllViewsOnPage() {
         removeAllViews();
+        mOnLayoutListener = null;
         destroyHardwareLayer();
     }