/*
 * call-seq:
 *      new( summ, msg, icon, widget )
 *
 * summ = The summary text ( required )
 *
 * msg = The body text or nil
 *
 * icon = The icon or nil
 *
 * widget = The widget (or a Gtk::StatusIcon, when compiled against GTK+ >= 2.9.2 and libnotify >= 0.4.1) to attach to or nil
 *
 * Creates and returns a new notification
 */
static VALUE
notification_init( VALUE self, VALUE summ, VALUE msg,
                         VALUE icon, VALUE widget ) {