2003-10-17  Murray Cumming  <murrayc@usa.net>

        * gtk/src/combobox.hg: Updated for latest API.
        * Added gtk/gtkmm/comboboxtext.[h|cc], putting text-based stuff
        in a sub class.
        * gtk/src/treemodel.[hg|ccg]: Added const overload of children(),
        but it's a bad hack that needs more attention.
        * Added examples/book/combobox, which uses ComboBoxText and should use
        ComboBox also in future. It segfaults at the moment.
        * Added gtk/src/toggleaction.[hg|ccg] and gtk/src/radioaction.hg.
        * Wrapped GList* and GSList*-using methods.
        * UIManager: Wrapped Error-using methods, with optional errthrow
          parameter of _WRAP_METHOD().
        * gtk/src/gtk_signals.defs: Updated with newly-generated defs from
        extra_defs_gen, redoing the by-hand corrections.
        * examples/book/dialogs/colorselection, fontselection: Used
        the buttons instead. This will be moved into the buttons folder
        later.
        * examples/book/dialogs/messagedialog: Updated for new constructor
        API.