[Cocos2d-JS]Add AssetsManager Chinese doc
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Merge branch 'master' of https://github.com/cocos2d/cocos-docs

Conflicts:
	manual/framework/html5/zh.md
Merge branch 'master' of https://github.com/cocos2d/cocos-docs
Merge pull request #309 from pandamicro/master

[Cocos2d-JS]Add AssetsManager Chinese doc