[Xmonad] darcs patch: make everything work with new doLayout. (and 1 more)

Hi all, Here's a cleanup of Combo (depends on rewrite of doLayout). David Sat Jun 23 14:09:52 PDT 2007 David Roundy * make everything work with new doLayout. This modifies all the contrib modules to work (so far as I know) with the new contrib layout. The exception is the LayoutHooks module, which isn't used. It exports an API that is inherently unsafe, so far as I can tell (and always has been). Sun Jun 24 10:13:46 PDT 2007 David Roundy * clean up code in Combo. This adds some type safety, since the super-layout is now of a distinct type from the sublayouts. This avoids the ugliness we had, of passing "fake" windows to the super layout. Now we directly lay out the layouts.