Fixed lighting, improved lights

Multiple lights work, limit@10 for now. Additional parameter,
light.power. Scale of 1-10+ directly affects the lights brightness.
light.intensity changed to work with the same scale. Both default to 1.

Old lighting algorithm made for a wide soft outer edge and  a pretty
much evenly lit core, which was honestly butt ugly. Current algorithm
has no distinctive edges, but is maybe a little bit to even.