Mostly so it actually works. I couldn't get a fully JS version working and I can't be bothered to when this seems to work.
Note that yes, the wasm IS checked in to the repository. This is just so clang isn't a direct build dependency, but will be needed if the decompression module needs to be updated.
msagent.js can now parse the character section of a ACS file fully.
This also adds a testbed thing. Later on it will display individual frames
and animations for debugging before the full character API is ready.
For now, it just has a file input for dumping ACS files into so we can debug
reading of the data.
