added Node::getCascadeBoundingBox()
replaced "NULL" with "nullptr"
moved getCascadeBoundingBox() to utils
call getCascadeBoundingBox() properly
remove external
add external submodule
update submodule on download-deps.py
add external submodule
Merge pull request #8117 from minggo/use-submodule-for-external

Use submodule for external
Merge pull request #1 from cocos2d/v3

- fastforward
* added default value for _batchNode in CCSprite
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
uncomment 3rd part bins check
Merge pull request #8101 from SunLightJuly/get_cascade_bounding_box

added utils::getCascadeBoundingBox()
[ci skip]
Merge pull request #8122 from andyque/fixJenkins

uncomment 3rd part bins check
Merge branch 'v3' of https://github.com/cocos2d/cocos2d-x into v3

Conflicts:
	external