BugFix: Demos of Pro-Midifiles contain stuck notes

It may happen that the demos of Pro-Midifiles contain stuck notes.

We will replace the demo files in a timely manner. Until then, please compare in such a case with the GM demo, as these don't have this errors.

We can assure that the stuck notes are not included in the purchase versions of the midi files, as these araise during the automated cutting of the demos.

UPDATE 07.12.: Demos are all updated...