[Xmonad] HEADS UP xmonad-library merge

[Don Stewart]

sjanssen:
> Firstly, because of all these changes, we recommend backing up your Config.hs
> before pulling these patches.
> 
> We've just merged the xmonad-library branch, which brings some major changes.
> 
> User configuration now goes in ~/.xmonad/Main.hs.  The installed xmonad
> executable builds and runs this configuration file at runtime.
> 
> XMonadContrib is now built and installed as a separate step, simply do the
> usual Cabal installation procedure after installing the xmonad library.
> 
> This is a big transition, bear with us as we smooth out the rough spots.

So don't use the head branch unless you're prepared to submit bug
reports :)

-- Don