This change adds feed forward terms for the voltage and current controllers. This allows including inputs using system parameters and knowledge not available to the PID controllers to improve performance.

Some examples of use cases might be using the moving inertia with an S-curve motion profile to calculate the torque (current) required to follow the profile. Without feed forward, following error depends solely on the PID controller, with feed forward the PID controller is only responsible for compensating unmodeled disturbances. Another example would be using a motor to resist a known load, like gravity, or a spring, while in angle or velocity control mode. This currently would depend on the PID controller to compensate for the load, but because the load is well known it can be calculated directly. The response of the system to predicable changes in this load no longer depends on the PID controller bandwidth.

This change still needs testing, but I wanted to get it out there while I had a chance. :)