Utility blocks when MIDI device is in use by another process

The utility blocks for no apparent reason when the MIDI device is in use by another process. The culprit seems to be line 30 in `midi.c`:
```r = snd_rawmidi_open(&handle_in, &handle_out, device, 0);```

If `SND_RAWMIDI_NONBLOCK` is set as the flags, then the utility properly exits with a human readable error:
```r = snd_rawmidi_open(&handle_in, &handle_out, device, SND_RAWMIDI_NONBLOCK );```

Start in midi.c at line 30, where snd_rawmidi_open is called, and reproduce the utility with the MIDI device occupied by another process. Confirm that the utility exits with a human-readable error instead of blocking when the nonblocking flag is used.

Written by the indexing model from the issue text.