Fixed a harmless bug where the Lank would try to add new sprites to old containers.

app/lib/surface/Lank.coffee

@@ -104,6 +104,7 @@ module.exports = Lank = class Lank extends CocoClass
       @sprite.destroy?()
       if parent = @sprite.parent
         parent.removeChild @sprite
+        if parent.spriteSheet is newSprite.spriteSheet
           parent.addChild newSprite
 
     # get the lank to update things