This package provides datatypes to construct Free monads, Free monad
transformers, and useful instances. In addition it provides the constructs to
avoid quadratic complexity of left associative bind, as explained in:
Janis Voigtlander, Asymptotic Improvement of Computations over Free Monads,
MPC'08/. http://www.janis-voigtlaender.eu/Voi08d.html