Revision 451

(ClassGrid): Moved OnCellDClick() from
        Classifier to ClassGrid. Added support for removing selected rows,
        which including code for keeping track of when cells are selected,
        and deselected.
(ClassTable): Support for added/removing rows. Fixed a problem
        with __ParseInput whereby it would not allow strings (only numbers)
        to be entered.
(Classifier): Added button and supporting code for removing selected rows.