Renamed gtk_image_menu_item_add_icon() to gtk_image_menu_item_set_icon()

Renamed gtk_image_menu_item_add_icon() to gtk_image_menu_item_set_icon()

2001-04-28  Martin Baulig  <baulig@suse.de>

	* gtk/gtkimagemenuitem.[ch]: Renamed gtk_image_menu_item_add_icon()
	to gtk_image_menu_item_set_icon() and made it work if there's already
	an image.
	(gtk_image_menu_item_new): This function doesn't take any arguments anymore.
	(gtk_image_menu_item_new_with_label): New function.