Refactor #3985: arguments length check replaced by undefined check in engine
Refactor #3985: arguments length check replaced by undefined check in extension
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into develop

# By Jose Antonio Andújar Clavell (1) and dingpinglv (1)
# Via dingpinglv (2) and Jose Antonio Andújar Clavell (1)
* 'develop' of https://github.com/cocos2d/cocos2d-html5:
  Bug in SceneReader setPropertyFromJsonDict
  Closed #3875: Refactoring cc.FadeIn and cc.FadeOut to fix a bug that its start opacity isn't current value.
Merge pull request #1551 from pandamicro/develop

Refactor #3985: arguments length check replaced by undefined check