Replicate the fix from https://github.com/net-lisias-ksp/AviationLights/issues/4

[Lisias]

Oukey,

We may have found the reason why some users report mysterious misbehaviours that I can't replicated on my rigs.

On net-lisias-ksp/AviationLights#4 , I apparently fixed one of these mysterious misbehaviours and, well, if AL could misbehave due the Update being called outside the intended Scene, then TweakScale may also.

I'm wondering if using the PartModule's OnUpdate would be a better idea, as hopefully it could handle this mess for us - or perhaps not, but I need to check first if the TweakScale's Update is being called outside the intended scenes (I'm betting it is).

[Lisias]

Labeled it as a bug, because if I'm right TweakScale would be misbehaving on these borderline situations.

Labeled also as an enhancement, as TweakScale should not had been forced to worry about this crap.

Labeled as "Not my fault" because… Well, it's not my fault! :)