cocos2d3 宏定义屏幕宽高，这样就不用重复获取了

#define SCREEN_WIDTH        CCDirector::sharedDirector()->getWinSize().width    //屏幕宽(指定分辨率)
#define SCREEN_HEIGHT        CCDirector::sharedDirector()->getWinSize().height    //屏幕高(指定分辨率)