EventDispatcher bug fix

Hi
This is EventDispatcher bug fix branch.
The issue occurs when...
1. Push the button. (So, EventDispatcher's _inDispatch > 0)
2. Create a layer.
3. Call EventDispatcher's addListenerSceneGraph to listen touch events. The node is the layer.
4. Not associated immediately. Because _inDispatch is bigger then 0.
5. Call Director's pushScene a scene that has the layer.
5. So when the layer is entering -> layer resumed -> calls EventDispatcher's resumeEventListenersForTarget -> cannot find the layer. -> added listener is not resumed. -> bug