added Node::getCascadeBoundingBox()
replaced "NULL" with "nullptr"
moved getCascadeBoundingBox() to utils
call getCascadeBoundingBox() properly
Merge pull request #8119 from SmartCat/v3

* added default value for _batchNode in CCSprite
[AUTO][ci skip]: updating cocos2dx_files.json
Merge pull request #8121 from CocosRobot/update_cocosfiles_1411435563

[AUTO][ci skip]: updating cocos2dx_files.json
Merge pull request #8101 from SunLightJuly/get_cascade_bounding_box

added utils::getCascadeBoundingBox()