add: Category.Applicative and Category.Monad
add: Abel.Data.Maybe.Applicative and Abel.Data.Maybe.Monad
add: Abel.Data.Product.Applicative and Abel.Data.Product.Monad
add: Abel.Data.Sum.Applicative and Abel.Data.Sum.Monad
add: Abel.Function.Applicative and Abel.Function.Monad
modified: Category.Functor (header)