Cleaned the comment for getting bodyname as an argument
(selecting the name is left to user to decide)
Override getPower method for BodyActuator
(compute power as F(dotProduct)V)
Marked override Actuator::addToSystem
(since it's already a virtual method of Component)
Edited comments for BodyActuator
Changes to get spatial forces in ground frame instead of body frame.
(Also some clean-up and use of more descriptive names)