[WIDL] Implement support for unique strings

[Robert Shearman]

Eric Kohl wrote:

>         case PASS_OUT:
>+            if (in_attr && has_size && pointer_type == RPC_FC_UP && phase == PHASE_FREE)
>+                break;
>             if (!out_attr)
>                 continue;
>             break;
>  
>

I don't think this is correct. Firstly, it should continue, not break. 
Secondly, I think it only doesn't need to free the string if it has a 
size. I'm pretty sure it shouldn't depend on being a unique string.

-- 
Rob Shearman