[xmonad] one more layout

[Daniel Schoepe]

Konstantin Sobolev wrote:
> I've submitted it with 'darcs send', thought it should find it's way
> to the mailing list.
> Anyway, here it is.

darcs send only works if your `mail' command works correctly, that is,
if you configured postfix/sendmail/whatever-mta-you-want correctly. If
you don't want to do that, you can save it via `darcs send -o
foobar.dpatch' and then attach the patch manually.