Humdrum markup inside of MusicXML data

[Craig]

Hello **HUGers,

I added a system for embedding Humdrum markup in MusicXML files so that much of the additional markup necessary after converting from MusicXML can now be done within a graphical music notation editor, such as MuseScore/Sibelius/Finale.

Tandem interpretations can be added as text expressions attached to notes in the editor such this example from the documentation of the new feature:

       https://doc.verovio.humdrum.org/interface/musicxml/#embedding-tandem-interpretations

Adding text expressions starting with an asterisk will be inserted directly into the converted Humdrum data as a tandem interpretation:

The converted Humdrum data and rendering in VHV or HNP:

The text expressions can be hidden in PDF output from MuseScore if you want to use the PDF for regular notation viewing as discussed in the documentation.

Local comments are also transferred via text expressions.  If a text expression starts with an exclamation mark (!), it will be copied verbatim into the Humdrum conversion as a local comment:

     https://doc.verovio.humdrum.org/interface/musicxml/#embedding-local-comments

This allows adding extra layout parameters to notes and rests as well as general comments.

And finally, reference records can also be embedded within the MusicXML data:

      https://doc.verovio.humdrum.org/interface/musicxml/#embedding-reference-records

The documentation also gives a demo of the header templating system to control the text displayed above the first system of music (when using HNP or creating a PDF in VHV, since the header is suppressed inside of VHV normally).

-=+Craig