DilloURL has a dtor.

It is the same as the original free function.  But this
will let me put some ownership on various members and slowly
start to C++ify this core type.

src/web.cc

@@ -152,8 +152,8 @@ int a_Web_valid(DilloWeb *web)
 void a_Web_free(DilloWeb *web)
 {
    if (!web) return;
-   a_Url_free(web->url);
-   a_Url_free(web->requester);
+   delete web->url;
+   delete web->requester;
    a_Image_unref(web->Image);
    dFree(web->filename);
    dList_remove(ValidWebs, (void *)web);