`Vector3d.Equals(object )` will throw if passed an object that isn't a `Vector3d`

[gotmachine]

Stupid mistake is stupid :

public override bool Equals(object other)
{
	if (!(other is Vector3)) // should be Vector3d
		return false;

	Vector3d vector3d = (Vector3d)other; // InvalidCastException when other isn't a Vector3d

	if (x.Equals(vector3d.x) && y.Equals(vector3d.y))
		return z.Equals(vector3d.z);

	return false;
}

Notably can cause issues for boxed Vector3d instances when inside object collections (which is a weird use case, but still).