[Xmonad] darcs patch: move Layout stuff into class (hokey firs... (and 3 more)

Here's a Read instance. Fri Sep 14 17:59:59 EDT 2007 David Roundy <droundy@darcs.net> * move Layout stuff into class (hokey first cut). Thu Sep 20 11:52:37 EDT 2007 David Roundy <droundy@darcs.net> * eliminate ugly OldLayout. Thu Sep 20 12:12:08 EDT 2007 David Roundy <droundy@darcs.net> * add Show instance to Layout Thu Sep 20 13:45:29 EDT 2007 David Roundy <droundy@darcs.net> * add Read instance to Layout.