-switching away from the JPL spherical polygon surface area strategy and returning to the `exact' solution approach (JPL solution was not performing any better with brief testing)
-coded a new function to calculate the surface area of a planar polygon with vertices in 3D cartesian space (based strongly on http://stackoverflow.com/a/12653810)
-coded a unit test for the planar polygon surface area function (seems to pass for a tilted rectangle in 3D space)