Fix usage of # and b in flatted and sharped chords

[yuma-m]

Currently, PyChord doesn't properly handle sharped or flattened qualities in chords.

For example,

>>> c = Chord("Dm7b5")
>>> print(c.components())
['D', 'F', 'G#', 'C']

The third note should be Ab instead of G#, as it is a flattened note of the fifth (A).

This PR addresses this issue by adding logic to the val_to_note method, which utilizes the quality name, and adds and fixes test cases.