Fix external link on pages list (#153)

layouts/partials/list.html

@@ -11,7 +11,7 @@
     {{ range .Paginator.Pages }}
     <li>
       <span class="date">{{ .Date.Format (.Site.Params.dateFormat | default "January 2, 2006" ) }}</span>
-      <a class="title" href="{{ .URL }}">{{ .Title }}</a>
+      <a class="title" href="{{ .Params.ExternalLink | default .URL }}">{{ .Title }}</a>
     </li>
     {{ end }}
   </ul>