Updates license to version 3 of the creative commons sharealike. By

Giles & Hansel.

Author: Resolver Developers

server/renderer/templates/tutorial_base.html

@@ -54,8 +54,7 @@ <h1 id="id_tutorial_title">{{ title }}</h1>
             {{ body }}
         {% endautoescape %}
     </div>
-    <a rel="license" href="http://creativecommons.org/licenses/by-sa/2.5/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-sa/2.5/88x31.png" /></a><br />This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-sa/2.5/">Creative Commons Attribution-ShareAlike 2.5 Generic License</a>.
-    
+    <a rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-sa/3.0/88x31.png" /></a><br />This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/">Creative Commons Attribution-ShareAlike 3.0 Unported License</a>.
     </body>
 </html>