Merge branch 'master' of https://github.com/cocos2d/cocos2d-js
Release #5636: Update beta upgrade guide
Release #5636: Update README and cocos2d-html5 ref
Merge branch 'master' of https://github.com/cocos2d/cocos2d-js
Merge pull request #551 from pandamicro/master

Release #5636: Update docs and cocos2d-html5 ref