Another attempt at getting Xrandr screen size changes right. Actually

Another attempt at getting Xrandr screen size changes right. Actually

        * gdk/x11/gdkevents-x11.c:
        * gdk/x11/gdkscreen-x11.[hc]: Another attempt at getting Xrandr
        screen size changes right. Actually handle XRRScreenChangeNotify
        events, and ignore root ConfigureNotify events if we are using
        Xrandr. Only emit size-changed signals if the screen size changed,
        and only emit monitor-changed signals if the monitors changed.

svn path=/trunk/; revision=22398