Afterburner

Afterburner 0.2.0. One version number for every build now. What a build contains depends on its Minecraft version.

**Changed**
- Far terrain (where the build has it) starts off: switch it on in Options > Video Settings > Afterburner. Far terrain saved by earlier versions is ignored, and a chunk copied before its light was worked out is no longer saved (that caused gray boxes and black wedges at the horizon).
- Page links, icon, license and third-party notices are in the jar.

**Fixed**
- Forge: a rare server crash while generating new terrain (`featureList is null`): Afterburner asks again, and falls back to one thread if a parallel step fails.
- Mixin config minimum version declared (an `ERROR` line in the server log is gone).

This build has the server-side optimizations and the client rendering ones. It does not have the experimental parts (shader pack loader, upscaling, far terrain) or the Minecraft 26.3 network features.