update facebook android sdk document
fix indentation
add publishInstall and logEvent
add to cross platform feature
fix format
Update en.md
Update en.md
Update en.md
Merge pull request #448 from timotei/patch-1

Update en.md
Merge pull request #447 from joshuastray/master

update facebook android sdk document
Merge pull request #450 from VisualSJ/master

Add Facebook payments api reference
Create ko.md
Update ko.md
remove useless code
Update zh.md
Merge pull request #453 from joshuastray/master

remove useless code
roll back to rc2, and add rc3 document
Merge pull request #455 from joshuastray/master

rollback Facebook Android ducument to rc2, and add rc3 document
Merge pull request #454 from purpleenjae/patch-2

Update zh.md
Merge pull request #452 from sincntx/master

[Cocos2d-JS] Add iOS IAP Korean doc