Notification on urgency flag patch

Hi all,

I was in IRC briefly last night enquiring about getting notifications
for non-visible windows which want the user's attention (bells in
xterms, message notifications in pidgin, that sort of thing)

I've attached a simple patch which adds functionality for detecting when
windows want attention, and displays a message showing the name and id
of the window. This is done by means of sending an echo command (which,
admittedly may not be the correct way to do this) to ratpoison.

I'm finding it quite useful so far, as I've previously missed urgent
windows due to a C-t Q or similar.

Eoin