xml2abc v1.68.3

This is an unofficial fork of Wim Vree's excellent xml2abc. Most likelly, this will be a mirror and the source for NPM packages that will make it easier to use the code via "npm i".

In the future, abc2web may be split to a separate git repo.

Official links here:

• https://wim.vree.org/js/
• https://wim.vree.org/js/xml2abc-js_index.html
• https://wim.vree.org/svgParse/xml2abc.html