Added reference to the official NSClient web site

git-svn-id: https://nagiosplug.svn.sourceforge.net/svnroot/nagiosplug/nagiosplug/trunk@274 f882894a-f735-0410-b71e-b25c423dba1c

plugins/check_nt.c

@@ -7,6 +7,8 @@
  * Copyright (c) 2000-2002 Yves Rubin (rubiyz@yahoo.com)
  *
  * Description:
+ * 
+ * This requires NSClient software to run on NT (http://nsclient.ready2run.nl/)
  *
  * License Information:
  *