[xmonad] Modular config

recompile calls ghc --make, but supplies the -i argument, which suppresses including the current directory in the search path. This means that one can't break up xmonad.hs into modules in their own .xmonad directory. I don't see any particularly good reason to prevent this, so here's a patch that removes the -i argument. An equivalent change would be to change "-i" to "-i.", which explicitly sets the search path, but the ghc docs state that this is the default anyway, so I think that removing it makes more sense.