Fix copyright and licensing already

[sneakernets]

The licensing and copyright on this is extremely messed up due to my ignorance in 2012-2016 when I started this. Dmxopl is technically MIT licensed. I also released it under a creative Commons license by accident on idgames but that was due to the doomworld boilerplate license generator.

As for copyright, oof, Me? I have no idea how copyright works!

I originally used Paul Radek's OP2 file as a base, which was already extremely modified by someone else on USENET because Romero put it up on USENET as a binary, without any copyright whatsoever, way back in late 1993. I cannot find who that was/they were who modified the files, it's not written down. No one thinks of this pesky stuff when they have deadlines and crunch.

Fraggle did string matching and found only a few instruments remained that were "Paul Radek" (maybe?) patches. Given that this is a ship of Theseus , especially with the file format changes, not a bit of that is really left.

I had to use Paul's work as a base when I started, because there was no way to not do that when I started, the technology wasn't there yet to do a "clean" version. When Wohlstand created the Opl3 Bank editor, I moved everything over to there. That's when @OlPainless and @freq-mod suggested some stuff (check commit history) along with Patch93 and others from the Fourth Modulator discord. All those submissions are in the repository.

The only person I cannot contact to get a blessing from this mess is Paul Radek. I have no clue how to contact him and make this right, so I can say "Copyright 20xx Shannon Freeman, et al." and put this to rest already.

And to quell any future potential anger, I have yet to receive a dime for all this work. It's kind of an industry secret that a lot of these OPL patches were passed around, swapped, ripped from other games and modified, etc. without any acknowledgment. I did not do any of that with DMXOPL, everything is documented.

Apologies for this mess!