[Xmonad] darcs patch: make Circle work with Layout class. (and 1 more)

This just saves one line of code... but also demonstrates the benefit of not requiring a modifyLayout to be defined, if the layout doesn't want to listen to messages. :) David Fri Sep 21 17:55:25 EDT 2007 David Roundy * make Circle work with Layout class. Sun Sep 23 07:52:57 EDT 2007 David Roundy * use default modifyLayout in Circle.