Determine the inertial characteristics of a flying bird. | 1. Determine the center of gravity of the bird's torso (including the legs) | 2. Calculate the inertia of the flight feathers about the tip of the calamus | 3. Determine the center of gravity of one of the bird's wings | 4. If computing for asymmetric case, input a different set of clean points (clean_pts) | 5. Combine all data and obtain the center of gravity, moment of inertia and principal axes of the bird