improve getnotes defaults for type-0 midi files

[ssfrr]

I was testing with the attached MIDI file, and ran into some issues that I think are related to the fact that it's a type-0 file. For instance, BPM(midi) throws an error, and getnotes requires that the track be specified as 1 (normally it sees to assume that the MIDI data starts on track 2, but type-0 files only have 1 track).

C Major.zip

[Datseris]

I don't understand the BPM part. There doesn't seem to be a BPM information in your track, or the existing code fails to see it. This is not relevant with it being type 0 or not, because running this piece of loop:

for event in t.tracks[1].events
        if typeof(event) == MetaEvent
            if event.metatype == 0x51
                tttttt = deepcopy(event.data)
                break
            end
        end
    end

Doesn't find the meta event that corresponds to the BPM signature. On the other side there is nothing wrong with the getnotes function:

julia> getnotes(f, 1)
25 Notes with tpq=96
 Note C4  | vel = 100 | pos = 0, dur = 48
 Note E4  | vel = 100 | pos = 0, dur = 48
 Note G4  | vel = 100 | pos = 0, dur = 48
 Note D4  | vel = 100 | pos = 48, dur = 48
 Note F4  | vel = 100 | pos = 48, dur = 48
 Note A4  | vel = 100 | pos = 48, dur = 48
 Note E4  | vel = 100 | pos = 96, dur = 48
  ⋮
 Note B4  | vel = 100 | pos = 288, dur = 48
 Note D5  | vel = 100 | pos = 288, dur = 48
 Note F5  | vel = 100 | pos = 288, dur = 48
 Note A5  | vel = 100 | pos = 288, dur = 48
 Note C5  | vel = 100 | pos = 336, dur = 48
 Note E5  | vel = 100 | pos = 336, dur = 48
 Note G5  | vel = 100 | pos = 336, dur = 48

Yes by default it chooses track number 2, as this is the most probable track to have notes for typical midifiles, but noone forces you to go with it.

[Datseris]

I guess we could improve the getnotes function to default to track 1 if the midi type is 0. So I'll put the tag "easy" here since it is a trivial fix.