issue #2254 : Add plugin weibo for iOS.
fixed #2254 : Add sample code for plugin weibo on iOS.
Merge branch 'master' of https://github.com/cocos2d/cocos2d-x
Update the JS binding code of plugin.
Merge branch 'master' of https://github.com/cocos2d/cocos2d-x
Merge pull request #2759 from natural-law/master

Add plugin weibo for iOS [master]