Tiny demo for MathML Accessibility

Early alpha stage.

Live demo at: https://dginev.github.io/tiny-mathml-a11y-demo

Method:

• obtain presentation MathML with accessibility annotations from a TeX formula, via the experimental LaTeXML accessibility branch
• render the MathML (with help from MathJax if needed), to sample the browser behavior
• also display the verbatim pMML syntax, made readable via highlight.js
• minimal javascript implementation of narrating a11y-enriched pMML trees into plain-text English.
• using speech-rule-engine as a baseline in narration text
• sample text-to-speech audio via a baseline neural engine by mozilla/TTS
• deploy on commit via gh-pages, making the project easy to fork and mod further.
• the latexml endpoint can be easily swapped with any other conversion service.

Known limitations:

• near-everything is at a "barely demoable" stage at time of writing, as this is a first draft of an implementation
• LaTeXML's accessibility annotations are ongoing work
  • multirelations and complex duals are just a couple of the cases with fishy markup
  • we need a tiny dialect of TeX macros to demo adding accessibility annotations to e.g. scripts, embellished variables, others...
• the baked-in narration implementation is kept simple:
  • lacks a coherent linguistic foundation, so readouts are bad
  • only covers a small number of semantic primitives
  • needs targeting, so that a narration is done in context and per-use.
• the showcase page is also limited
  • more of the examples need annotating, and we generally need even more examples, maybe a gallery?
  • responsive tables are difficult in HTML,
  • ended up patching the minimal theme too much, can be organized better
  • jQuery is a bad foundation for a 2020 user interface, only works if this demo stays tiny.