Consider a SmallBounded type

[bbarker]

As an alternative to #35 that is a bit easier to deal with but slightly less safe (though unless you are doing some crazy stuff, should be fine most of the time), I would like to ask if we could do the following, and thus resurrect e.g. boundedEnumMaybe:

-- | A lawful class to denote Cardinality a << Cardinality Int
class Bounded a <= SmallBounded a

instance boundedEnumMaybe :: (SmallBounded a, BoundedEnum a)
  => BoundedEnum (MaybeWrapped a) where
    cardinality = Cardinality $ unwrap (cardinality :: Cardinality a) + 1
    toEnum 0 = wrap  Nothing
    toEnum n = wrap $ Just <$> toEnum (n - 1)
    fromEnum Nothing = 0
    fromEnum (Just e) = fromEnum e + 1