Contravariant Coyoneda, with tests for Order.
Make ContravariantCoyoneda more like Coyoneda.
Flip members.
Remove self binding; it is unused.
Scaladoc for the abstract members of *Coyoneda.
Move the schwartzian* members to tests.
Replace Coyoneda.apply with a fully-powered version.

* The old Coyoneda.apply is now called 'lift'.

* Both *Coyoneda have 'unlift' aliases for 'run'.

* More construction facilities for Coyoneda copied from
  ContravariantCoyoneda.

* Coyoneda is now sealed.

* Coyoneda only has abstract values now, no abstract methods, and
  there is only one (private) concrete class.
Flip the apply arguments and remove most implicits.
Minor doc fixes.
Start a ContravariantCoyoneda example.
ContravariantCoyoneda example: most of the basics.
Finish contravariant coyoneda example.
2.9.3 compilation.
fix #662 "Multiple evaluation of arguments in tuple instances"
Another property needed to derive associativity.
Transpose args, refer to usage example in ContravariantCoyoneda doc.
The InvariantFunctor rule isn't strong enough; just require associativity directly.
Fix indentation after <-.
Dangling comment.
Merge pull request #677 from S11001001/topic/coyoneda-contravariant-coyoneda

Contravariant coyoneda; move Coyoneda API around a bit