[xmonad] Andrea's screenshots and DecorationMadness

[Don Stewart]

roma:
> Ogedei @ IRC noted that some screenshots which are linked from haddock
> are not available. Precisely, these are arossato's screenshots.
> It's not hard to remove all broken links to screenshots, but the
> question arises concerning DecorationMadness module.
> Without screenshots it's utility becomes questionable. Sure some
> examples will go to Decorations haddock, but do we still need that
> module?

The plan last I heard was to turn DecorationMadness into documentation
only , in Decorations.hs

Feel free to do this.