Fixed #4277: update readme of Cocos2d-html5
Merge branch 'master' of https://github.com/cocos2d/cocos2d-js into Iss4277_ReleaseV3.0
Merge pull request #154 from dingpinglv/Iss4277_ReleaseV3.0

Fixed #4277: update readme of Cocos2d-html5