Deprecated constructor fix

lib/geshi/geshi.php

@@ -594,7 +594,7 @@ class GeSHi {
      *               {@link GeSHi->set_language_path()}
      * @since 1.0.0
      */
-    function GeSHi($source = '', $language = '', $path = '') {
+    function __construct($source = '', $language = '', $path = '') {
         if (!empty($source)) {
             $this->set_source($source);
         }