Cleaned-up and commented getPower and computeForce methods of BodyActuator
Fixed reading different states for the two test cases in testActuatorsCombination
Marked override addToSystem also in base Actuator class.
(since it's already a virtual method of Component)
Changes in testActuatorCombinations to cover more generic cases.
(in particlar testing use of 3D pointActuator,
double-checking if physically valid)
Fixed reading states for the two test cases as well in testBodyActuators.
(also changed torque axis, note it should be only in global/body frame for this actuator)
Edited bodyActuator to get if frame_is_(global unless body) as an argument.