improvement of midi import: grace notes / monophone instruments

I have 2 proposals for an even better midi import (which works very good even today!):
- provide possibility to mark a note line as monophone
- support recognition of grace notes

about monophone instruments: often midi files have been created using a keyboard (that are polyphone) for all instruments. In some cases notes of this instrument overlap due to this fact. This makes the import create a 2nd voice for this instrument (the normal behaviour).

The better import would look like this, because the instrument is monophone.

Technically this would mean that any new note would stop the former note so that only one note needs to be played for this instrument.

The 2nd item applies to situations like this:

The first 2 notes normally would be notated as grace notes, making the reading and understanding easier for the musician.
Technically this might be solved by making all notes that are shorter than the max. quantization set for the import will be transformed to grace notes.

Once more I like to say that the import works almost perfect for most cases. The things above are just a "Sahnehäubchen" (I don't know the english word for this).