More Syntactic Sugar for Vecs

[alegian]

defines the infix function cross for Vec3 and Vec3i.

val example = vector1 cross vector2

These extension crosses all fallback to the underlying class for implementation.

All other vector util classes seemed incompatible:

• Vec2 does not make sense mathematically
• Vector4dc, Vector4fc, Vector3dc and Vector3fc implement cross in a slightly awkward way which cannot be infixed: this.cross(other, dest), and I decided to not overload it

[thedarkcolour]

I just overhauled the project setup, you'll have to remake your PR

[thedarkcolour]

You can add loader-agnostic Minecraft extensions under the kfflib.common source set. https://github.com/thedarkcolour/KotlinForForge/tree/5.x/src/kfflib/common/kotlin/thedarkcolour/kotlinforforge/forge/vectorutil