add simple smtp-settings test-page, fixes #464

Signed-off-by: Michael Kaufmann (d00p) <d00p@froxlor.org>

lib/navigation/00.froxlor.main.php

@@ -313,6 +313,10 @@ return array(
 				array(
 					'url' => 'admin_message.php?page=message',
 					'label' => $lng['admin']['message']
+				),
+				array(
+					'url' => 'admin_settings.php?page=testmail',
+					'label' => $lng['admin']['testmail']
 				)
 			)
 		)