Import midi file: use instruments in file by default

[teo8976]

When importing (uploading) a file, you have to manually choose the instrument for each channel.

This is stupid, since the file most of the times already contains the "program change" commands. You should by default use the program changes in the file and map them to the corresponding GM instruments.

This should be obvious.

[cork]

There are over a hundred MIDI instruments/patches but only a few that are supported in the Sequencer. Also, notice that there isn't a drum instrument. That is because you change the channel setting to 10 in the MIDI channel setting. I don't know if Sequencer can recognize that, but I wouldn't count on it when changing everything. To be able to import other instruments than the ones supported would mean that the Sequencer would have to support those instruments.