The removal of GtkBin and GtkContainer has required changes in all classes
that inherited from those classes. There are no longer Container::add() and
Container::remove() methods. Each type of container widget has its own
methods for adding and removing children.

gtk_dialog_run() has been removed, which affects most uses of Gtk::Dialog
and its cubclasses.

There are problems with this patch. At the time of writing everything
compiles and links. But many test programs and demo programs crash, or
misbehave in other ways. Gtk::Dialog::run() has not been correctly
replaced everywhere.