Closes #8

* Add Chebyshev2D departure term type

* A fully encapsulated library wrapper with C++ interface

* Refactor types.hpp to hide the big headers in a macro conditional section

Why does Catch not capture the exception?

* Split out reducing and mutants to their own headers

* Remove unused function

Add runtime test

Add test and expose in Python

By adding the necessary Eigen header for real type of autodiff

Next is the cross derivatives

Added a mockup of how one would hardcode models into the shared library (a la CoolProp), dynamic loads just need to be replaced with hardcoded strings, probably encoded as binary

Couple of inlines are needed to avoid duplication of functions between compilation units