[openbox] Logout, suspend, shutdown, reboot window

[seanh]

Hey, thought some others might find this useful:

https://gist.github.com/seanh/6417375

It's a script that, when launched from a keybinding or menu in openbox,
shows a simple window with cancel, logout, suspend, reboot and shutdown
options. It uses GTK and dbus.

It'd based on an older script that I found somewhere and used for a
while. IIRC the older script used the gdm-control command. But Ubuntu no
longer uses GDM by default (I'm on Ubuntu 13.04) so it stopped working.
My new one works with 13.04.