add en.md
create ja.md

create ja.md
update
Update ja.md
Create ja.md
Update ja.md
Create ja.md
Update ja.md
Update ja.md
Update ja.md
Create ja.md
Update ja.md
Update ja.md
Update ja.md
Update ja.md
Update ja.md
Create ja.md
Update ja.md
Update ja.md
Merge branch 'master' of https://github.com/cocos2d/cocos-docs