issue #3713:fix memory leak of autoreleas pool
Merge branch 'iss3713-replace_CCObject' of https://github.com/minggo/cocos2d-x into iss3713-replace_CCObject
issue #3713: use reference in loop
issue #3713: every autorelease will cause a release operation
Merge pull request #5151 from minggo/iss3713-replace_CCObject

fix memory leak of autorelease pool