[xmonad] darcs patch: SmartBorders even for empty layouts (and 1 more)

Hi, I did the full, proper fix by merging emptyLayoutMod into redoLayout. I did not test all affected modules, but Haskell’s type system makes me confident that this was a proper refactoring. Greetings, Joachim Sun Oct 5 20:44:26 CEST 2008 Joachim Breitner * SmartBorders even for empty layouts Fixes: http://code.google.com/p/xmonad/issues/detail?id=223 Sun Oct 5 21:02:20 CEST 2008 Joachim Breitner * Merge emptyLayoutMod into redoLayout This removes the emptyLayoutMod method from the LayoutModifier class, and change the Stack parameter to redoLayout to a Maybe Stack one. It also changes all affected code. This should should be a refactoring without any change in program behaviour.