The one you’re linking to is on the “master” branch, as you can see in the URL. The latest work has been going on in the release branch, and that’s where you need to look if you want the new UV generation code.
But don’t worry too much about that in this case, what you really want are proper UVs, not auto-generated ones.
You are correct that Away3D has no capability of generating relevant UV information. It can only create dummy UVs, which will make sure the object renders without crashing, but it will not wrap the texture around the object in a way that actually makes visual sense. You indeed have to take care of that mapping yourself in some 3D modeling package. Away3D is a rendering engine, and while it does have some good geometry generation tools and utilities, it is not intended to be used for UV unwrapping. The reason simply being that your texture has to be painted to match the UV mapping, so making the UV mapping at rendering time defeats the purpose. Here’s what a workflow should (and usually does) look like:
1. Create model
2. Unwrap model
3. Paint texture on unwrapped UV layout
4. Apply texture (or don’t, and do it in code instead
5. Export model with UVs
6. Load model in Away3D
7. Optionally apply texture (if one wasn’t included in the model file)
As you can see, doing step 2 in Away3D makes little sense, because then you wouldn’t be able to paint or preview your texture (steps 3-4) in your modeling package.
These circumstances, together with the fact that automatic UV unwrapping is extremely complicated (no modeling packages I know of do a very good job at it) and resource heavy means it would be a huge effort to implement in Away3D, that goes mostly wasted simply because it doesn’t make much sense to use it at all in most cases.