Add support for flat notes, fix wrong position and frequency

[simonppg]

No description provided.

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟢	Statements	98.89% (+0.59% 🔼)	178/180
🟢	Branches	94.34% (+0.22% 🔼)	50/53
🟢	Functions	97.73% (+2.27% 🔼)	43/44
🟢	Lines	98.84% (+0.62% 🔼)	170/172

Test suite run success

40 tests passing in 9 suites.

Report generated by 🧪jest coverage report action from 9a3c2fa

[github-actions]

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
lib/Accidental.d.ts, lib/Accidental.js, lib/Accidental.js.map, lib/Chord.d.ts, lib/Chord.js, lib/Chord.js.map, lib/ChordsFormula.d.ts, lib/ChordsFormula.js, lib/ChordsFormula.js.map, lib/Frequency.d.ts, lib/Frequency.js, lib/Frequency.js.map, lib/IntervalPattern.d.ts, lib/IntervalPattern.js, lib/IntervalPattern.js.map, lib/Main.d.ts, lib/Main.js, lib/Main.js.map, lib/Math.d.ts, lib/Math.js, lib/Math.js.map, lib/Note.d.ts, lib/Note.js, lib/Note.js.map, lib/NoteDTO.d.ts, lib/NoteDTO.js, lib/NoteDTO.js.map, lib/NoteParser.d.ts, lib/NoteParser.js, lib/NoteParser.js.map, lib/NoteValidator.d.ts, lib/NoteValidator.js, lib/NoteValidator.js.map, lib/Scale.d.ts, lib/Scale.js, lib/Scale.js.map, lib/ScaleFormatter.d.ts, lib/ScaleFormatter.js, lib/ScaleFormatter.js.map, lib/ScalesCode.d.ts, lib/ScalesCode.js, lib/ScalesCode.js.map, lib/math/Binary.d.ts, lib/math/Binary.js, lib/math/Binary.js.map	12.87 KB (+0.45% 🔺)	258 ms (+0.45% 🔺)	800 ms (+2.83% 🔺)	1.1 s