add a functional interface to allow speed to vary with distance for auton

[gabrielseaver9678]

In AutonDrive and AutonDriveSimple, speed is passed to the command as a double through the constructor method. I believe AutonDrive has an option to reduce the speed as the robot approaches the endpoint, but it’s clunky and only works so well.

Try to implement a system which allows a functional interface (taking proportion of distance to the endpoint as a parameter) to be passed in instead of a double to AutonDrive and AutonDriveSimple.

Make sure to talk to me before you implement this, though—I’m not quite finished with setting up all the other systems which you’ll need before adding this functionality and I’d like to talk before anyone spends time working on this.