unnecessaries removed.
fixed a bug in sort first underscore function
Merge branch 'uidev-dashboard' into uidev
Merge branch 'hotfix' into uidev
fixed a bug about negative offset at onTail event
validateWidgetContext function and test added
asset must have own validator
widget context validator test case modified
added WidgetService
Merge branch 'uidev' into uidev-dashboard