Instrument importer cannot import multiple files about opn2bankeditor

[Wohlstand]

Hello!
Since its creation, its supposed to import one single file, but, thanks for a note about instument files. Anyway, that will also require me to add the "absolute assignment" feature to let users define where to store every instrument. Right now, you can select a target slot via main window while instrument file is open.

What about GYB/VGM importer case, it's because the program changes some characteristics other than just a volume, and causes these differences being treated as different instruments. That's need to add some more options to detect such cases and squash these siblings into single entries.

Off topic: I was the whole month being ill and I was mostly inactive this time (sounds like I got some kind of the flu, and also, several buddies in different cities and even countries got ill too), but these weeks I getting better and better.