matchfile v1.0.0 voice parsing fix

[huispaty]

This PR fixes bug #267 for voice parsing from match files of version 1.0 (the most current one) that follow the v+digit(s) pattern

• Voice info is now parsed as follows: If there is no voice info, all notes get assigned voice number 1. If there is only voice info for the solo voice, the non-solo voiced notes get voice 2. If multiple notes have different voices, but not every note has a voice annotated, those with voice annotation get the annotated voice number and those without voice annotation get assigned the max voice+1 voice number.
• The unittest now contains an assertion for match voice parsing from v1.0.

[sildater]

this only adds voices equal to one in case all voices are None. Maybe something like

n_voices_num = [n.voice for n in part.notes if n is not None]
n_voices_none = [n.voice for n in part.notes if n is None]
new_voice = 0
if len(n_voices_num) > 0:
    new_voice = max(n_voices_num ) + 1
if len(n_voices_num):
     -> the loop