Neo-Riemannian Player

This is a refactored version of this repository, and is still in the state of testing.

Roadmap

1. [checked] Learn iced framework
2. [checked?] Find a suitable structure for multi-threading-supporting note states
3. [checkde] Implement standard operations on note states
4. [ongoing] Find an algebra-geometry relation between states and Tonnetz. This time, try to avoid using graph data structure
5. Define Tonnetz and dual-Tonnetz
6. Recreate algebraic-BFS from the previous repository
7. Plot note state with iced
8. UI design