Changed the copyright year to 2015

COPYRIGHT.txt

@@ -1,4 +1,4 @@
-Supervisor is Copyright (c) 2006-2013 Agendaless Consulting and Contributors.
+Supervisor is Copyright (c) 2006-2015 Agendaless Consulting and Contributors.
 (http://www.agendaless.com), All Rights Reserved
 
   This software is subject to the provisions of the license at