instanceOf now uses RTTI and checks its answer.

Next I'll just remove it, but this commit lets me
have something in history such that I can fall back to
check for bugs that might get introduced.

src/html.cc

@@ -798,7 +798,7 @@ bool DilloHtml::HtmlLinkReceiver::click (Widget *widget, int link, int img,
       /* Change the link color to "visited" as visual feedback */
       for (Widget *w = widget; w; w = w->getParent()) {
          _MSG("  ->%s\n", w->getClassName());
-         if (w->instanceOf(dw::Textblock::CLASS_ID)) {
+         if (w->instanceOf<dw::Textblock>()) {
             ((Textblock*)w)->changeLinkColor (link, html->visited_color);
             break;
          }