Generate final classes for syntax.
Regenerate and adapt manual hacks to parent.
Clean up ==>> Functor stack; ==>> is Bifoldable too.

* Add an explicit left-fold for Foldable ==>>.

* Merge all Functorish into mapTraversable, renamed mapCovariant.

* Traverse[[S]S ==>> A] doesn't need Order[S].

* Specialized fold/map will be used even if Order[S] is available.
Remove redundant ==>> tests.
Intersection semigroup & union monoid for ==>>.
Optimize #equal for ==>> Order.
Rewrite mapShow with contramap.
Promote arbitrary ==>> to scalacheck-binding.
Test soundness (order preservation) of a few ==>> operations. (union fails)
Symmetricity and more idempotence tests.
More ==>> difference tests.
Implementing the :<: (inject) type class
Adding Scala 2.9.3 support
Correct issue with union - my mistake.

Signed-off-by: Gary Pamparà <gpampara@gmail.com>
Added Cord isEmpty() and nonEmpty().
A failing ==>> intersection sample.
A sample of intersection failing.
a intersect a = a
partition soundness
Renaming :<: to Inject and Scalaz integration