Measure refactor match/midi/musicxml

[sildater]

refactoring for new measure attributes for match/midi/musicxml and internal funx, both input and output

inputs:

• import_midi: uses score.add_measures which uses both fields
• import_match: match parses measures as noted in the match file, especially incomplete ones (see also creating a score with load_match discards measure information #246)
• score.add_measures: consistent with the Measure class, separate handling of anacrusis measure removed
• note_array_to_score: consistent with the Measure class

outputs:

• export_musicxml: uses name now
• export_match: is fine, uses its own measure format, neither name nor number
• export_midi: is fine, uses measures only for ts changes, neither name nor number

misc:

• type casting in import_musicxml
• fix durations in für elise test match file