Issue #4757: update a mistake of CHANGELOG
Merge branch 'master' of https://github.com/cocos2d/cocos2d-js into Iss4757_ReleaseV3_A2
Issue #4757: update the reference of cocos2d-html5
Merge pull request #271 from pandamicro/master

Issue #4749: Fix Xcode < 5.1 compile problem with spider monkey
Merge pull request #272 from dingpinglv/Iss4757_ReleaseV3_A2

Issue #4757: correct a mistake of CHANGELOG and the reference of cocos2d-html5
Add the new JavaScriptStyleGuide.html page
Merge pull request #273 from VisualSJ/master

Add the new JavaScriptStyleGuide.html page
Add upgrade-guide to docs
Merge branch 'master' of https://github.com/cocos2d/cocos2d-js
Add release-note to docs