Fixed: consonance_maker now works for -P4 intervals in dissonance.py

Perfect fourths arising from inversion are now also examined by the
special_fourths method to determine whether they are consonant or dissonant.
Fixed: neighbor note detection in dissonance.py

Neighbor notes are detected correctly and false positives have been removed.
Fixed: Passing tone detection in dissonance.py.

Passing tones are detected correctly and voice crossings are no longer
problematic.
Fixed: detection of dissonant fifths as neighbor tones in dissonance.py

Now neighbor tones that are dissonant fifths (either diminished or augmented)
are detected and marked accordingly. In some cases one may wish to call a
perfect fifth a neighbor note but these are not detected as the fifth in
question is consonant. But this is probably only an issue in two voices,
because with more voices the neighbor tone will inevitably be dissonant against
another voice.
Fixed: detection of dissonant fifths as passing tones in dissonance.py

Dissonant fifths can now be detected as passing tones. This will probably
make the most impact in two-voice textures where there are not additional
parts that the passing tones would get detected against. Also, this should
allow for the labelling of two consecutive passing tones in a single voice
such as the line G-F-E-D over a sustained B. The F and E will now each
be labelled as passing tones.