Vectors and Quaternions should be immutable

[in2dair]

We're repeatedly running in to subtle bugs when we grab vectors/quaternions off of a transform (e.g., for math), and then inadvertently modify the source.

position = actor.transform.app.position;
rotation = actor.transform.app.rotation;
// DANGER! don't modify position or rotation or you'll mess up actor's transform

There are workaround (e.g., explicitly cloning), but the developer remains in constant danger of shooting themselves in the foot :)