Harte-library

🐛 Bug Fixes:

* Solved bugs reported in https://github.com/andreamust/harte-library/issues/29 and related to the `HarteInterval` module, for which some intervals where not converted correctly to `music21.Interval`
* Now chords with double flat bass are fully supported (c.f. https://github.com/andreamust/harte-library/issues/29)
* Improved code readability

🐛 **Bug Fixes:**

- Resolved issue where prettify function was not returning the bass note.

✨ **Added Features:**

- Implemented `multi_hot_encoding()` method, which returns the multi hot encoding of the chord.
- Implemented transpose in the `multi_hot_encoding()` method, which returns the transposed multi hot encoded chord.

🐛 **Bug Fixes**:

- Resolved issue where * (removed) degrees in Harte syntax were not properly removed.
- Fixed behaviour: N now correctly returns empty chords when applicable.
- Completed comprehensive code reformatting for enhanced readability and performance.

✨ **Added Features**:

- Implemented initialisation of octaves for each note. Now, if the bass note is not the root, it is automatically set to a lower octave (3).
- Introduced get_midi_pitches method, facilitating retrieval of a list of MIDI pitches for each note within the chord.

This release fixes a known issue:
✅ Added a new exception if an empty chord is passed to the `Harte` constructor, since empty chords are not supported by the `music21.chord` module.

The release fixes two main bugs 🐛:
- adds support for _'N'_ chords, previously unsupported
- fixes the problem where chord ranks were not ordered correctly.

Second stable release which fixes most of the bugs in the chord recognition and implements unit tests.