allow tpl_getFavicon() returning the absolute path to the icon file

inc/template.php

@@ -1346,10 +1346,13 @@ function tpl_flush(){
  *
  * @author Anika Henke <anika@selfthinker.org>
  */
-function tpl_getFavicon() {
-    if (file_exists(mediaFN('favicon.ico')))
-        return ml('favicon.ico');
-    return DOKU_TPL.'images/favicon.ico';
+function tpl_getFavicon($abs=false) {
+    if (file_exists(mediaFN('favicon.ico'))) {
+        if($abs) return ml('favicon.ico', '', '', '', true);
+        else return ml('favicon.ico');
+    }
+    if($abs) return DOKU_URL.substr(DOKU_TPL.'images/favicon.ico', strlen(DOKU_REL));
+    else return DOKU_TPL.'images/favicon.ico';
 }