Exporter: Scene to osu! storyboard

[nahkd123]

Low priority task.

• Only compatible with sprites and containers for now.
  • Box2D and other vector objects can't be loaded by the game.
  • While we can try to convert vector objects into sprites, it might affect the SB load due to huge number of sprites required (in case the object is animated with keyframes).
• Cubic bezier easing function may not work.
  • We can run the curve through all easing functions to see which one is closest, or we can split our curve into multiple segments and put them together as keyframes with linear easing function, but may affect SB load.
• Modifiers that use features that doesn't exists on the SB engine will not work.
  • Such things like shadow, blur or compositing mode will not work.
  • Modifiers that only applies translation, rotation or scale will work, since SB engine supports these 3 transformation types.