Access to cpp.Struct fields when wrapped as Dynamic (and in cppia?)

Let's say `Native` is a c++ struct with a `float foo` field.

```haxe
final n:Native = allocNativeSomehow();
final s:cpp.Struct = n;
trace(n.foo); // works
final d:Dynamic = s;
trace(d.foo): // null
```

It would be nice to generate a Dynamic wrapper for each `cpp.Struct` with proper reflection support. And I assume it is possible (?) because the type information of `Native` is known by Haxe at compile time.

I also assume that would enable access to cpp.Struct from cppia as well?