整理样式，添加注释
Merge pull request #29 from RubyLouvre/master

merge from RubyLouvre/onionui
Merge branch 'master' of https://github.com/ilife5/avalon.oniui

merge
增加onShow onHide回调函数
修改doc文档
Merge pull request #100 from ilife5/master

整理dropdown样式，添加注释