Tiny changes + small updates

To be honest I was feeling too lazy to publish such small changes, but I changed my mind.

- Added a simple main menu illustration (no more ugly default background)

- Added a BANGING title theme

- Changed unknown characters' name tags to reflect that

Outlines for part 2 and 3 are written out in more detail, and making good headway on part 2! Script and sprites are in the works. roughly 20% done. Estimated playtime hopefully 15 minutes?

I can't guarantee that I will release part 2 on its own, both due to how the story for part 2 is written and the precedent it would set for length between updates. I feel that it wouldn't be as gratifying, but I am undecided on this. This is my first VN, and my first publicly released story in general. I'm only used to making art and writing private, short stories, so really I'm winging my way through this whole thing. A final decision will be made either once I'm finished with part 2, or once I already have the beginning of part 3 done.