Move wallpapers to external activity

Also renaming Launcher's ApplicationInfo to
AppInfo since ApplicationInfo is already a 
framework class

Change-Id: Ib3e91d2ba4ace458d790a26c0ce850870fd3f146

src/com/android/launcher3/Folder.java

@@ -1090,9 +1090,9 @@ public class Folder extends LinearLayout implements DragSource, View.OnClickList
 
     public void onDrop(DragObject d) {
         ShortcutInfo item;
-        if (d.dragInfo instanceof ApplicationInfo) {
+        if (d.dragInfo instanceof AppInfo) {
             // Came from all apps -- make a copy
-            item = ((ApplicationInfo) d.dragInfo).makeShortcut();
+            item = ((AppInfo) d.dragInfo).makeShortcut();
             item.spanX = 1;
             item.spanY = 1;
         } else {