-Voronoi_polygons_spherical_surface() method now returns a useful dictionary data structure containing the surface areas of the Voronoi regions (and the associated generator information) -- dictionary_Voronoi_region_surface_areas_for_each_generator
-added an optional sphere_radius argument for the initialization of Voronoi_Sphere_Surface instance, because using the centroid distance to estimate radius may not always be appropriate based on generate bias at one pole, etc.
-adjusted the two surface area reconstitution unit tests to use the new surface area data structure produced above
-the regularly-spaced generator surface area reconstitution unit test now passes (randomly-generated still fails, but again is probably acceptable for now)