Removed NLog dependency, as it was primarily used for debugging. In cases when an error occurs (most likely incorrect arguments), an exception is thrown now, instead of fixing the arguments and logging a message.

Extending PointOctree with non-alloc query methods and unifying the signature of non-alloc query methods with BoundsOctree.
Targeting .NET Standard 2.1 and .NET Framework 4.6.2 from now on.

Use System.Numerics.Vector3 instead of custom Point type for built-in SIMD operation support.
Targeting .NET Standard 2.1 and .NET Framework 4.6 from now on.

Generate XML-doc and add to NuGet package.

Targeting .NET Framework 4.5.2 beside .NET Standard 2.0.

Initial versioned release. Public NuGet release.