Find a better way to shuffle

[pvsr]

I copied a snippet from the haskell wiki for shuffle :: [a] -> IO [a] which added dependencies on array, mtl, and random. random is of course reasonable, and array isn't a big deal since it's a core package, but requiring mtl just for liftIO is lame. On top of that, the function itself is pretty ugly.

[pvsr]

Actually now that I think about it mtl is already a transitive dependency through libmpd.