Added allowempty setting to ISEMAIL validator.

Till Brehm

2016-01-29 a8ab61eeb0beac52d5a1e8c41d549df4ed87bf71

 interface/web/tools/interface_settings.php

@@ -126,7 +126,7 @@
         print '<script type="text/javascript">document.location.reload();</script>';
         exit;
      }
      else parent::onShow();
      //else parent::onShow();
   }