Feature #5033: refactor Widget,Layout,Button,Checkbox
Feature #5033: refactor ImageView,LoadingBar,RichText,Slider,Text,TextAtlas,TextBMFont,TextField
Feature #5033: refactor ListView,ScrollView,PageView
Feature #5033: Make ccui classes extendable in H5 and JSB
Merge pull request #1855 from joshuastray/develop

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