Computation times

00:22.532 total execution time for 7 files from examples/04-lights:

Example	Time	Mem (MB)
Shadows (shadows.py)	00:08.221	0.0
Plotter Lighting Systems (plotter_builtins.py)	00:07.818	0.0
Light Types (light_types.py)	00:02.208	0.0
Light Actors (actors.py)	00:01.505	0.0
Beam Shape (beam_shape.py)	00:01.344	0.0
Disabling Mesh Lighting (mesh_lighting.py)	00:00.798	0.0
Attenuation (attenuation.py)	00:00.638	0.0