Changed to moves, and renamed the exposed attributes

* Adding the 2-Center Lennard-Jones model developed by Mecke and the revised version of Lisal

* Added dipolar and quadrupolar contributions to 2CLJF model

Yet another forceeval

Found the first real bug in autodiff: https://github.com/autodiff/autodiff/issues/242

And add test

And to python interface

Hours later...

Yet another battle with typing

It works!

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

* Bump version to dev

Closes #8