issue #4116: Remove script-bindings codes, move it to 'cocos2d/cocos2d-js' and 'cocos2d/cocos2d-lua' repo.

The innovation of cocos2d will be faster by separating scripting support to different repositories. 
New repo: 
For JS bindings: https://github.com/cocos2d/cocos2d-js
For lua bindings: https://github.com/cocos2d/cocos2d-lua