Sakuya Izayoi v2

Sakuya has gotten a major overhaul in terms of sprites, including a whole new look with a new signpost sprite and everything.

Major thanks goes to MoonyExclipsy for collaborating with me on this. I hope you all enjoy racing as her as much as we did making her. :)

Been meaning to get around to sorting this out for some time now.

Here is what was changed.

• Sakuya's sprites no longer have seemingly random "grey pixels" on them.
• Changed Sakuya's minimap icon.
• Updated Sakuya's signpost with a change for better consistency.