Small cutscene addition and pure reset for beating campaign — Touhou Volleyball Danmaku Steam update #618915

A small cutscene has been added to all character intros who are not Reimu, Marisa, Sakuya, or Remilia. After your character's story, Sakuya will appear and tell you the objective of the game. I also fixed an oversight where the game doesn't reset completely after beating the story campaign with a character. Now the game starts from a clean slate, with only your Survival high score remaining untouched.