RAAML — correct attribution of the GSN standard and derived material

The GSN standard is made available under creative commons licence version 4. This allows free use but requires appropriate attribution, which could be accommodated in the reference in section 3.3, or in section 4.
“GSN Standard V2 License: This work is licensed under the Creative Commons Attribution 4.0 International License.
To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.
You are free to share the material in any form and adapt the material for any purpose providing you attribute the material to the SCSC ACWG, include the license details above and indicate if any changes were made. See the license for full details.”

Reference creative commons license

Add creative commons acknowledgement for GSN standard.