Using the plant output means that measurement noise can be incorporated.
SingleJointedArmSim (in C++ and Java) and ElevatorSim (in C++) used the
state instead of the measurement.
Closes#3042
This includes physics simulation support for arms/elevator models, as well as differential drivetrains.
Swerve might be added at a later date.
Co-authored-by: Claudius Tewari <cttewari@gmail.com>
Co-authored-by: Prateek Machiraju <prateek.machiraju@gmail.com>
Co-authored-by: Tyler Veness <calcmogul@gmail.com>
