Porting PagedView from KG to gain simplified scaling model, reordering

-> We are no longer scaling individual Celllayouts, instead we are scaling
   the entire Workspace (and the CellLayouts come along for the ride)
-> Due to the above change, many assumptions were broken. In particular,
   our drag and drop / animation archiecture is fairly fragile due to the
   frequent and complex mapping of points between different bits of the
   hierarchy. This CL contains a number of fixes which address such
   breakages.

Change-Id: I2e630eab17528729b764b61f587858f6499fd318
diff --git a/res/layout-land/launcher.xml b/res/layout-land/launcher.xml
index 5fe05dd..6dfbf21 100644
--- a/res/layout-land/launcher.xml
+++ b/res/layout-land/launcher.xml
@@ -35,6 +35,7 @@
             android:id="@+id/workspace"
             android:layout_width="match_parent"
             android:layout_height="match_parent"
+            android:layout_gravity="center"
             android:paddingStart="@dimen/workspace_left_padding"
             android:paddingEnd="@dimen/workspace_right_padding"
             android:paddingTop="@dimen/workspace_top_padding"