About potential regression

[targos]

Hi @andcastillo.

I am doing some cleanup on this package, and splitting it into multiple projects for more visibility on npm. I wonder about the rationale for the PotentialRegression class. I understand that it is a special case of the polynomial regression but I am not sure why there is a class especially for this case and also where the name "potential" comes from? I couldn't find a reference on the web.