Drop2+: extends drop2 to most common chord types & voicings

EDIT: For discussion see: https://musescore.org/en/node/356955
EDIT: fixed bug with pickup measure without chord symbol
EDIT: Tuplets are now handled correctly in in xdrop2+.qml.
EDIT: Mu4 port in myDrop2.qml, see https://musescore.org/en/node/356955
Proceed as follows: copy a lead sheet into the right hand and also into the left hand staff (there without the chord symbols (use F6)) of a piano score. Don't worry about the looks.
For details: see the lines if (e.tuplet) {
duration *= e.tuplet.actualNotes/e.tuplet.normalNotes;
}
in function add1drop2.

EDIT: Added an extra version xdrop2+.qml with even more voicings that avoid dim substitutions.
EDIT: Improved the (buggy) findchord routine.
The plugin will look for a voicing of the current chord that can accomodate a given melody note. If no such voicing is found, the dim voicing will be used. This is the basic drop 2 concept.

See C-voicings.mscz for a list of chord types & voicings considered (x 12 keys in the plugin).

Proceed as follows: copy a lead sheet into the right hand staff of a piano score where the left hand is filled with eight note rests, as in test.mscz (This is needed to create the segments needed in the left hand).

Run the plugin from the Plugin Creator window. To test run the plugin on test.mscz and you should get result.mscz.

Any chord symbol that is not recognized will result in insertion of dim chords. See C-voicings.mscz for the chord symbol style I use.

Enharmonic chords and notes are/should be OK.

Known limitations:
Ties between notes have to be restored manually.
Melody notes may be replaced by their enharmonic equivalent.
Max melody notes & chords is set to 512. Adjust if you need more.
Melody notes in triplets are not handled correctly.Tip: use the Duration Editor plugin to convert occasional triplets to regular notes, back & forth, in a scratch file.

Please report issues in the forum.