-voronoi_utility.py:
	-increased the stringency for rotation of unit normals in produce_array_Voronoi_vertices_on_sphere_surface()--to prevent spurious reflections about the sphere--this seems to produce a reasonable Voronoi diagram based on visual inspection alone [though I do wonder if my pseudo-arbitrary cutoff of -0.1 for delta will cause problems in some cases--will need to test eventually...]
	-some new assertions to increase code integrity