Revision 415

(ClassGrid): New class to represent a
        custom grid.
(ClassTable): Support for editing Values and Labels and for
        changing what type (point or range) of data is stored in each
        property based on how the user enters the data.
(Classifier): Support for saving the new classifications and
        launching the dialog to edit a property.
(SelectPropertiesDialog): New class for editing the visual
        properties of a classification (stroke color, width, and fill color)
(ClassPreviewer): Took the Draw method from ClassRenderer and
        made most of it into this new class. Intend to use this class in
        the SelectPropertiesDialog for previewing changes.