Remove Zip[[a]These[X, a]]; it is unlawful.
Add &&& as a proper name for These#zip.
Deprecate These#zip; the name implies the existence of a lawful instance.
Promote arbitrary ==>> to scalacheck-binding.
Test soundness (order preservation) of a few ==>> operations. (union fails)
Symmetricity and more idempotence tests.
More ==>> difference tests.
fix CoproductInstances. add Equal instanse
CoproductArbitrary
add CoproductTest
add UnwriterTTest
Correct issue with union - my mistake.

Signed-off-by: Gary Pamparà <gpampara@gmail.com>
Merge pull request #499 from S11001001/topic/no-these-zip

Remove Zip on These and deprecate These#zip
Merge pull request #503 from xuwei-k/coproduct

fix CoproductInstances
A failing ==>> intersection sample.
A sample of intersection failing.
a intersect a = a
partition soundness
Merge pull request #507 from gpampara/map-union-fix

Correct issue with ==>>#union. Fixes #501
fix scalaz.==>> bug