Make it work in Node about rustify

[yoshuawuyts]

@goto-bus-stop was thinking the same.

---

But, maybe you don't always want a webassembly module instantiated immediately, instead waiting for some event to instantiate it, so idk what's better.

This should work for async initialization; it's a single step instead of two, is all.

emitter.on('some-event', async () => {
  var mod = await rustify('./add')
  console.log(mod.add_one(1))
})

[goto-bus-stop]

I think calling lib/rustify to get the same behaviour in Node might be difficult because it is asynchronous, while the rust`` template tag is 'synchronous' (once compiled through rustify). maybe i'm missing something.

#4 would help with this actually because we could return a Promise that does lib/rustify and then instantiates the WebAssembly module.

But, maybe you don't always want a webassembly module instantiated immediately, instead waiting for some event to instantiate it, so idk what's better.