Added COPYRIGHT statement

COPYRIGHT

+ETSI FORGE COPYRIGHT STATEMENT
+
+Copyright (c) ETSI 2018.
+
+This software is subject to copyrights owned by ETSI. Non-exclusive permission 
+is hereby granted, free of charge, to copy, reproduce and amend this file 
+under the following conditions: It is provided "as is", without warranty of any 
+kind, expressed or implied. 
+
+ETSI shall never be liable for any claim, damages, or other liability arising 
+from its use or inability of use.This permission does not apply to any documentation 
+associated with this file for which ETSI keeps all rights reserved. The present 
+copyright notice shall be included in all copies of whole or part of this 
+software and shall not imply any sub-license right.
+