[xmonad] ScratchWorkspace

[David Roundy]

I've just pushed in a ScratchWorkspace module that defines a scratch
workspace.  You can look at Config.Droundy to get an idea how to use it (as
it's undocumented).  It's still very crude, and anyone who wants to take a
shot at cleaning it up is welcome to try.  The main issue is that the
scratch workspace is available as a "normal" workspace, which I find a
little annoying.  I'd prefer it remained hidden until I asked for it.  But
I can't quite see how to do that, either.

Enjoy! (and comments/suggestions are welcome, although I've really already
wasted more time on this than I ought...)
-- 
David Roundy
Department of Physics
Oregon State University