Task #9607: proper filtering on duration

SAS/ResourceAssignment/ResourceAssignmentEditor/lib/static/app/controllers/gridcontroller.js

@@ -46,6 +46,7 @@ $scope.columns = [
     { field: 'duration',
         displayName: 'Duration',
         width: '6%',
+        type: 'number',
         enableFiltering: false,
         enableCellEdit: false,
         enableCellEditOnFocus: false,