Store last pitch and duration per voice/part/section

[ciacob]

The last pitch and duration entered by the user should not be stored globally. Especially when entering two-voice music, it is useful to keep track of each individual voice's level, so if I entered a middle C in voice 2 and a middle G in voice 1, the next pitch I should be proposed in voice 1 should be "G", whereas in voice two it should be "C", and they shouldn't mix. The same logic should be applied to durations. It might be able to extend this approach to parts and sections.