fixed up GridFilter so it won't show the summary if there are no filter values after getting processed after DisplayFilter events (so that a block can change a filter value to NULL  in the DisplayFilter event to hide it from the Filter Summary)
CheckinScheduleBuilder now always shows the CategoryPicker in the main UI instead of in the Filter.  This way it is more obvious that a selecting a Category is important for this UI to work.  Also changed the ParentLocation dropdownlist to a LocationItemPicker