Closed #2829: improving audio compatibility for mobile browser.
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into Iss2829_ImproveAudioCompatibility
Merge pull request #1281 from dingpinglv/Iss2829_ImproveAudioCompatibility

Closed #2829: improving audio compatibility for mobile browser.