Added support for Greek. Thanks Chris K!

includes/locale.php

@@ -66,6 +66,9 @@ if (empty($_SESSION['locale']) && strlen($_SERVER['HTTP_ACCEPT_LANGUAGE']) >= 2)
         case "vi":
             $locale = "vi_VN.UTF-8";
             break;
+        case "el":
+            $locale = "el_GR.UTF-8";
+            break;
         default:
             $locale = "en_GB.UTF-8";
             break;

includes/system.php

@@ -116,7 +116,8 @@ function DisplaySystem()
         'es_MX.UTF-8' => 'Español',
         'fi_FI.UTF-8' => 'Finnish',
         'si_LK.UTF-8' => 'Sinhala',
-        'tr_TR.UTF-8' => 'Türkçe'
+        'tr_TR.UTF-8' => 'Türkçe',
+        'el_GR.UTF-8' => 'Ελληνικά'
     );
 
     if (isset($_POST['system_reboot'])) {