Disturbance Observer

Description

Added DisturbanceObserver class that is built in to RobotController. Sandbox program DisturbanceObserverTest demonstrates its ability to estimate forces applied to the robot endpoint.

DisturbanceObserver makes use of the VectorBuffer, which is, just like it sounds, a buffer for holding vectors. Its purpose is to simulate a time delay. (Maybe there is a smarter way to do this, but I couldn't think of one.)

I also filled in missing comments for some of the classes in BurtSharp.Control.

What to focus on

• Disturbance observer test is working as expected.