discontinue scalaz-seven branch
Add IsomorphismOptional trait.
Merge pull request #768 from hgiddens/isomorphism-optional

Add IsomorphismOptional trait.
Added pure/point for Free monad
Merge branch 'scalaz-seven' into series/7.1.x

Conflicts:
	README.md
Free is a monad in an endofunctor category.
Free is a higher-order monad.
use NaturalTransformation.refl