Elm2node: transform an elm module to a synchronous node module

Ok cool @dta! Thanks.

There are no way to guarantee that a given value x returned by an “elm-converted-to-js” function cannot be modified by JS code. So I’ll never try do allow things like:

// js file:
var someOpaqueElmValue = elmModule.f(42);
var result = elmModule.g(someOpaqueElmValue);