How should class objects created in betterC be destroyed

[ryuukk_]

Here is how adam seems to be doing it: 
https://github.com/adamdruppe/webassembly/blob/731a7033174127c0a6dd4f23eabdb440adab286b/arsd-webassembly/object.d#L650-L681

Specially here:

```D
void destroy(bool initialize = true, T)(T obj) if (is(T == class))
{
(..)
     else
     {
         // Bypass overloaded opCast
         auto ptr = (() @trusted => *cast(void**) &obj)();
         rt_finalize2(ptr, true, initialize);
     }
}
```


and for interface:

```D
cast(Object)obj
```

But i suspect you'll have to implement the whole typeinfo