Allow us to set .sprite files as backgrounds

[165your4]

Allows for animated backgrounds. You could also allow us to set the background's sprite action through scripting (like what is possible with FloatingImages), e.g. the level background is a volcano, once the player flips a lever the volcano in the background begins to erupt

[weluvgoatz]

This is a nice idea... but I think someone made a similar issue, no? See #385

[Frostwithasideofsalt]

Someone should work on this lol