Feature #5033: add _ctor for ccui classes and modify init funcitons
Feature #5033:modify format
 Feature #5033: add extend function for ccui classes
Merge branch 'master' of https://github.com/cocos2d/cocos2d-js into extend_ccui
Merge pull request #372 from joshuastray/extend_ccui

Feature #5033: Make ccui classes extendable in H5 and JSB