Revert "Obsolete function, obsolete variables, name changing"

src/ZMPRefTrajectoryGeneration/ZMPVelocityReferencedQP.cpp

src/ZMPRefTrajectoryGeneration/ZMPVelocityReferencedQP.h

src/ZMPRefTrajectoryGeneration/generator-vel-ref.cpp

src/privatepgtypes.h