Removes unneeded ‘clone’ in cocos2d_specifics.cpp.
Updates bindings-generator, skips to bind override functions.
Removes unneeded ‘override’ codes, uses `using Node::addChild;` to prevent compiler warnings.
Merge pull request #4600 from dumganhar/remove-unneeded-bindings-codes

closed #3480: Removes unneeded codes of override function.