More testing is still needed to identify other issues

I am confused...

And add test

Stopped iteration if dx values are all < 0

And to python interface

Hours later...

Oddly this fixes the error in derivative, but it should have no impact

Temporaries were being returned when autodiff was being used, forceeval should fix it I think

Yet another battle with typing

It works!

* Add ability to access a single departure term in a multi-fluid model

* Bump version to dev

* 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