Fixing up some Folder bugs

-> Rendering properly while in spring-loaded mode
-> Fixed bug where sometimes the folder's background would vanish
-> Fixed bug where the folder background was "stuck" in a fixed
   location, not following the folder
-> Can now add to folders and create folders from spring-loaded mode

Change-Id: Ie1c5583a6230a192e6d07763d001b50053daca43

src/com/android/launcher2/DragSource.java

@@ -18,6 +18,8 @@ package com.android.launcher2;
 
 import android.view.View;
 
+import com.android.launcher2.DropTarget.DragObject;
+
 /**
  * Interface defining an object that can originate a drag.
  *
@@ -29,5 +31,5 @@ public interface DragSource {
      */
     void onDragViewVisible();
 
-    void onDropCompleted(View target, Object dragInfo, boolean success);
+    void onDropCompleted(View target, DragObject d, boolean success);
 }