[Xmonad] darcs patch: eliminate a few Eq a constraints in Stac... (and 2 more)

Here's a patch to start moving Layout into the StackSet. David Thu Sep 20 17:01:43 EDT 2007 David Roundy * eliminate a few Eq a constraints in StackSet. Thu Sep 20 17:05:27 EDT 2007 David Roundy * remove unneeded Ord constraint. Thu Sep 20 17:28:43 EDT 2007 David Roundy * add (unused) Layout to StackSet.