Improvement Plugin EnhancedLogin

- A validation was added validation for login.

workflow/engine/classes/class.plugin.php

@@ -42,6 +42,7 @@ define('PM_CREATE_NEW_DELEGATION',   1013);
 define('PM_SINGLE_SIGN_ON',          1014);
 define('PM_GET_CASES_AJAX_LISTENER', 1015);
 define('PM_BEFORE_CREATE_USER',      1016);
+define('PM_AFTER_LOGIN',             1017);