This crate implements a PID controller as described in
text
Åström, K. J., & Hägglund, T. (1988).
Automatic Tuning of PID Controllers.
Instrument Society of America (ISA).
ISBN 1-55617-081-5
This crate is currently experimental and should not be used yet.
This project steals from pid-rs the idea of being generic over a real number type.
This crate got its start at Grapl, Inc.