by qianjun;add scrollbar to simplegrid and dropdown
by qianjun;merge
by qianjun;fix scrollbar bug;add scrollbar to simplegrid
update
Merge pull request #80 from gogoyqj/master

修复scrollbar的bug，并调整接口、逻辑设置，给dropdown和simplegrid增加scrollbar
Merge branch 'master' of https://github.com/RubyLouvre/avalon.oniui

Conflicts:
	dropdown/avalon.dropdown.html
merge