1st Improvement Update

Hello, this is IvoryHand.

The 1st improvement update for Signanota has been applied.
The following changes are included in this update:

* Partial improvement of sound effects and UI
* Bug fixes and stability enhancements

The 2nd update is already in development and will be released in the near future with further improvements.

We sincerely thank all players for supporting and enjoying Signanota.