Changes to haddock

Changes to haddock:
commit 91e2c21cfdaca7913dbfec17bdd7712c0c1ed732
Author: Mateusz Kowalczyk <fuuzetsu@fuuzetsu.co.uk>
Date:   Wed Feb 19 05:11:34 2014 +0000

    Use a bespoke data type to indicate fixity

    This deals with what I imagine was an ancient TODO and makes it much
    clearer what the argument actually does rather than having the user
    chase down the comment.