Use well-formed boilerplate for compatibility with package.el

You mentioned kakapo-mode in https://github.com/haskell/haskell-mode/issues/366#issuecomment-61135843, and I thought I'd go ahead and add it to MELPA, but it first has to use the standard formatting for its boilerplate.

I've refrained from making further fixes, like converting all the `;` comments into `;;` -- I guess you would need `kakapo-mode` just to let Emacs put those `;` at those columns! ;-)