this is a helper kind class which receives all touch events and disapatch to the right object according
 to their display order

this is a helper kind class which receives all touch events and
disapatch to the right object according
 to their display order, just like the uikit doing,
 u dont have to add delegate with priority every single time when u
want an object receiving touch event.
 it will free u from complicate touch priority in cocos2d normal way