Closed #5588: fixed a bug of MouseEventDispatcher that it can't receive mouse move event on canvas after double click.
Merge branch 'v2.x' of https://github.com/cocos2d/cocos2d-html5 into Iss5588_MouseEventDispatcher
Merge pull request #1934 from dingpinglv/Iss5588_MouseEventDispatcher

Closed #5588: fixed a bug of MouseEventDispatcher that it can't receive mouse move event on canvas after double click.