Fixed an iOS9 issue with CCScrollView whereby gesture recognisers that were not being removed when the node was hidden, or removed from the node tree were being added a second time.  iOS8 and earlier allowed this even though it wasn't correct.  iOS 9 prevents this from working anymore.
Fixed an iOS9 issue with CCScrollView whereby gesture recognisers that were not being removed when the node was hidden, or removed from the node tree were being added a second time.  iOS8 and earlier allowed this even though it wasn't correct.  iOS 9 prevents this from working anymore.

cocos2d/cocos2d-objc,oxeron/cocos2d-objc,oxeron/cocos2d-objc,cocos2d/cocos2d-objc