[Xmonad] darcs patch: add sketch of tabbed layout.

This is pretty crude, but might interest others. I haven't yet gotten the click stuff working, though. :( It does display the tabs, at least (albeit without labels, but that should be easy). David Sat Jun 9 12:42:22 PDT 2007 David Roundy <droundy@darcs.net> * add sketch of tabbed layout.