Fix midi export

[Heiko Rufan]

SMF.write() does not work:

There is a wrong type hint in the signature (SMF instead of SMFData).

Also, the sorting method can lead to note_on events being sorted before note_off events when they have the same timestamp. This can corrupt the output file.

Attached is a diff for the fixes.

Thanks for the great work!

[きのもと結衣]

Thanks for report. and I will implement for running status that note_on velocity 0 as note_off.

[きのもと結衣]

34cc61ed2131dc83a24c0a23d4bb1395b494a174 で対応

[Heiko Rufan]

There is another issue here I did spot at first: If you have a program change or other control change at the same time as a note-on, you want these to be processed before the note-on.

So the logic here should rather be: If several events have the same timestamp, note-on must always come last.

[きのもと結衣]

In the first place, it is best to allow sorting to be turned on or off.
They should have been originally generated in sequence.

[きのもと結衣]

I implemented sort toggle argument at 60d578bb80fede1db51e09f8d0cf393175505ee4.