Add math

[73jn]

Possibility to export mathematical functions. Closes #276, #237

[VVsxmja]

You can enable automatic linebreaking↙️ to avoid overflow when a math expression is too long.

<script type="text/x-mathjax-config">
  MathJax.Hub.Config({
    extensions: ["tex2jax.js"],
    tex2jax: {
      inlineMath: [ ['$','$'] ],
      displayMath: [ ['$$','$$'] ],
    },
    "CommonHTML": { linebreaks: { automatic: true } },
    "HTML-CSS": { linebreaks: { automatic: true } },
  });
</script>