Problem: compile-time time arguments remapped to runtime arguments, in future the runtime arguments should come after the model

* Add methods for calculation of pure fluid critical points

* Pass the template arguments along

* Expose the values and Jacobian

Closes #8

* Add Chebyshev2D departure term type

* Add partial molar volume as a possible output

* And expose to python

* A fully encapsulated library wrapper with C++ interface

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