MathML support

[jtrakk]

MathML is the next generation of math display for the web. There are several tools for converting Latex code to MathML code, but there are also other languages that can convert to MathML. I am wondering if the parsing and rendering engines could be separated out so we can be agnostic about the input language, process an abstract math element, and render into Makie.

[Kolaru]

The parsing and engines are already separated, and linked by an abstract representation. So if you can parse MathML to the internal representation (nested TeXExpr) the layouting can be done straightforwardly.