return TRUE for GtkWidget::delete_event to avoid destruction of our float

return TRUE for GtkWidget::delete_event to avoid destruction of our float

Thu Mar 12 20:17:47 1998  Tim Janik  <timj@gimp.org>

        * gtk/gtkhandlebox.c (gtk_handle_box_delete_float): return TRUE for
        GtkWidget::delete_event to avoid destruction of our float window.

        * gtk/gtkmain.c (gtk_main_iteration_do): GDK_DELETE will destroy a
        widget if the last handler returned FALSE or there was none connected.

        * gtk/testgtk.c: adapted all delete_event/destroy case that were affected.

        * gtk/gtkwidget.c (gtk_widget_delete_hides): new function that will hide
        a widget and return TRUE to avoid window deletion if
        connected to GtkWIdget::delete_event.