I fixed the render interuption problem, which presumably got passed on to
everyone else. I think it's fixed in the last compile I released too.
I'm not certain if I included code to turn off dispersion if the amount is set to
1, though I think I did that too. Hmm...
One more thing. Although dispersion 1.1 or 1.2 can look nice, more accurate
values are like 1.001.
-Mike
