Javascript CAS

[josephlewis42]

The use of emscripten to generate the CAS is unfortunate because we end up with a very large package that takes a long time to download/parse.

BeanCounter should include a Javascript CAS instead. There are a few available, although it may be handy to just build a new one.

There is a professor emeritus at the University of Denver that's written a book on implementing CAS systems, it could be a good place to start.