[xmonad] [patch] EwmhDesktops: make setActiveWindow set _NET_WM_STATE for gtk-3.4

Hi, I am not an expert on EWMH but this change seems to be necessary for coming GTK 3.4, when using themes like Adwaita, that now supports @theme_unfocused_fg_color which causes unfocused application's UI to be rendered unfocused in addition to the normal unfocused window manager decoration. Current desktopConfig triggers this causing all Gtk3 apps to be rendered as unfocused. Anyway I would appreciate review of this patch and feedback: perhaps there is a better more correct fix? I am planning to apply a patch for this shortly to Fedora 17 xmonad-contrib, otherwise GTK apps in gnomeConfig etc look terrible. There are more technical details in the changelog. I haven't found any other window manager that triggers this issue yet. Jens