Utilities to test laws

[neutropolis]

Each optic algebras comes along with the laws that it should hold. We provide a ScalaCheck hook to test them, but it turns to be useless, since generating the evidences that it requires is quite a challenge. For example, we should be able to create Equal evidences for StateT programs. This task consists on analyzing these aspects and determine if this is viable. Perhaps, part of the functionality that we need would be contemplated in puretest.