[Cocos2d-JS] Polish Facebook docs
[Cocos2d-JS] Add Facebook chinese landing page
Merge branch 'master' of https://github.com/cocos2d/cocos-docs

Conflicts:
	manual/framework/html5/facebook-sdk/en.md
[Cocos2d-JS] Polish Facebook docs
[Cocos2d-JS] Fix doc root issues
Merge pull request #575 from pandamicro/master

[Cocos2d-JS] Polish Facebook docs