EMI: Save and restore SetShadow data.

The set shadow data was previously not saved and restored. I assumed before that Set::loadBinary would be called also when restoring a game, but this is not the case.

Not saving and restoring the shadow data had the side effect that if the game was saved in a set that has shadows enabled, the shadows would not be correctly deactivated when leaving the set after restoring the save. This caused rendering issues and crashes.