Quaternion.dq constructor
Constructs a quaternion from time derivative of q with angular
velocity omega.
Implementation
factory Quaternion.dq(Quaternion q, Vector3 omega) =>
    new Quaternion._()..setDQ(q, omega);Constructs a quaternion from time derivative of q with angular
velocity omega.
factory Quaternion.dq(Quaternion q, Vector3 omega) =>
    new Quaternion._()..setDQ(q, omega);