Added ellipsoids to the set of objects supported by the simple Whitted style ray tracer  we developed for the CMDA 3634 course @Virginia Tech for Fall 2018.
To detect collisions between sphere and ellipsoids we use a Newton based algorithm for finding the nearest point on an ellipsoid to another point from Robert Nümberg using his notes. Remarkably it appears to have worked perfectly first time!
 Whitted, T., 1979, August. An improved illumination model for shaded display. In ACM SIGGRAPH Computer Graphics (Vol. 13, No. 2, p. 14). ACM.