Lexing input via wasm now works

[mike-lischke]

I just pushed a number of changes that make lexing input complete (and only lexing). While that seems not worth to be mentioned it involved solving a number of fundamental problems with respect to generating the wasm file, handling memory properly, interaction with JS (including deriving a JS class from a C++ class) and more.

If you want to give it a try check out the repo and run npm i in its root. Additionally, you need emscripten installed as described in the readme.

Then run the build-wasm NPM script and once that finished (which can take a while) run the "Launch ANTLR4 Test" task to run the test.ts script. It will print a number of tokens from the WhiteboxLexer.ts.