Implement scrolling sfx in OptionLists

This means that scroll_values_left/right() in BattleSetting will need
to take the Sound as an argument, as the BattleSetting decides whether
to play the Sound or not.
OptionList: Reduce CONFIRM_DURATION
Decouple IntroAnimator from TitleState

This is, once again, for the sake of testability.
The TitleState's background and logo Animations will instead be passed
as arguments to IntroAnimator during each update.