[i18n] Add helper to sfController to translate messages

Author: GromNaN

lib/action/sfComponent.class.php

@@ -156,6 +156,20 @@ public function logMessage($message, $priority = 'info')
     }
   }
 
+  /**
+   * Gets the translation for the given string
+   *
+   * @param  string $string     The string to translate
+   * @param  array  $args       An array of arguments for the translation
+   * @param  string $catalogue  The catalogue name
+   *
+   * @return string The translated string
+   */
+  public function __($string, $args = array(), $catalogue = 'messages')
+  {
+    return $this->context->getI18N()->__($string, $args, $catalogue);
+  }
+
   /**
    * Returns the value of a request parameter.
    *