void RK4Integrator(int &nj, const double &t, double &dt, KDL::JntArray &q, KDL::JntArray &q_dot, KDL::JntArray &torques, KDL::Wrenches &f_ext, KDL::ChainFdSolver_RNE &fdsolver, KDL::JntArray &q_dotdot, KDL::JntArray &dq, KDL::JntArray &dq_dot, KDL::JntArray &q_temp, KDL::JntArray &q_dot_temp)