Issue #3501: update engine version number
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into Iss3501_ReleaseV2.2.2
Issue #3501: Update AUTHORS for Releasing v2.2.2
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into Iss3501_ReleaseV2.2.2
Issue #3501: fixed a bug of WebAudioEngine that it don't add sfx object to _effects when the audio didn't preload.
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into Iss3501_ReleaseV2.2.2
Merge pull request #1380 from dingpinglv/Iss3501_ReleaseV2.2.2

Issue #3501: Do something for releasing v2.2.2