code: public void rotate(Quaternion rotation) {
      	Transform3D m = new Transform3D();
      	m.makeRotationMatrix(rotation);
      	mul(m);
      }
docs: Rotate the object.
  <p>
  This function is equivalent to (where r is the translation
  of the quaternion as a 3x3 matrix):
  <pre>
  this = this *  [   r    r     r     0   ]
  [   r    r     r     0   ]
  [   r    r     r     0   ]
  [   0    0     0     1   ]
  </pre>
  
  @param rotation