modularizing for npm etc

[bkardell]

So this needs a bit more, but realistically, if you have this branch checked out and a modern version of nodejs installed you should be able to type (from the root of the directory)

npm install

and once that is done, switch to src and write a test.js which is as simple as

const { convertUnicodeToMathML } = require('../src/index.js');
const result = convertUnicodeToMathML('x^2');
console.log(result)

(from the src directory) running node test that should yield a logged MathML string. If we finish this, we register a build with npm and it makes it so that people can just add a dependency in their package.json to get support.

IF this works, for you, aside from the bits about where those files should go, there are some other things to cleanup which I haven't committed in order to focus what we're looking at. I also have changes to ../playground/index.html (to ) and ../utils/generate-parser.html (to put the format to commonjs)