* Better handle multiple tags respecting US format
Based on unversioned, V1 & V2 of US formats : https://github.com/UltraStar-Deluxe/format
Should address #623
Creator now takes multiple values
Maintain backward compatibility
* Update file path properties to match US formats
* Apply R# clean-up for reliability
- Migrate to NUnit4 Assert.That
- Update dependencise versions
- Fix LangVersion to 9.0 (until net core migration)
- Reformat code
- Apply 'var' style (easier for refactoring)
- Remove redundant parentheses
- Add braces on every condition blocks (1 line)
- Uses new null checking patterns
- Uses AutoProperties when possible
- Uses string scalar type instead of class
- Clean usings
- Add .orig files in git ignore
- Rename some properties to respect defined conventions and US format definition
- ID -> Id
- BPM -> Bpm
- Finish -> End
* Update R# settings according to the clean-up made
Quentin Bray