[Xmonad] darcs patch: The road to killing possibleLayouts: add... (and 2 more)

This is an exploratory change to remove possibleLayouts. I'd like to get some opinions on this patch before I push it. Cheers, Spencer Janssen Thu Oct 4 15:05:59 CDT 2007 Spencer Janssen <sjanssen@cse.unl.edu> * The road to killing possibleLayouts: add subLayouts Thu Oct 4 15:14:01 CDT 2007 Spencer Janssen <sjanssen@cse.unl.edu> * Remove possibleLayouts Thu Oct 4 15:31:45 CDT 2007 Spencer Janssen <sjanssen@cse.unl.edu> * subLayouts for Layout