The game would try to catch up in frames when a window prompt was
opened, so if the window was open for 140 frames the game would process
the next 140 frames instantly after the game was closed. To fix this, I
have the window prompt time how long it's opened and then I tell the
game to sleep for however many frames it was opened for.
Credits message works but does not yet have all the desired features,
will finish up later.
With these changes the game technically never "allows" you to quit, and
instead the input is handled by Scene_Map. This lets us run an event
before they quit.
This lets the user fadein bgm after using a normal "play bgm" command in
the event editor. Just simply call "Script.fadein_bgm(target, speed)"
with the target being the target vol % that you want the fade in to
eventually reach and the speed being how fast you want it to reach it (1
- slowest, 100-instant)
