enable to set color per poly.

Hi, I'm very happy to use your code!
I'm a developer / VJ / LJ live in Tokyo.

I'm operating laser in ILDA, and developed inteactive laser in DMX.
So I'm very happy to find this.
But I want to set color per poly, so I add this feature, though I add little code.

I sent my pull request if it is useful for some developers.
I'm happy if you accept my pull request.


Thanks,
Mitsuru

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Here is my project.
I was developped this system.
https://www.youtube.com/watch?v=LHSiEhbAWSo