add en.md
issue #3539, rewrite JSB manual binding sample for 3.0.
Merge branch 'master' of https://github.com/u0u0/cocos-docs
issue #3539, fix spell error.
Merge branch 'master' of https://github.com/cocos2d/cocos-docs
review
Merge branch 'master' of https://github.com/cocos2d/cocos-docs
issue #3539 add one article about JSB
issue #3539, review and modify
issue #3539 modify doc-style and some detials
Merge branch 'master' of https://github.com/cocos2d/cocos-docs
Merge branch 'master' of https://github.com/cocos2d/cocos-docs
fixed #3539, review and modify.
Merge pull request #81 from u0u0/master

fixed #3539, update sample code and articles for 3.0