Creative commons license footer.

Change license to CC-BY-NC-BD. While there, use the new mirror that
Creative Commons have for the license button.

templates/base.html

@@ -60,7 +60,11 @@
                     ·-->
                     <a class="atom" href="{{ FEED_DOMAIN }}/{{ FEED_ALL_ATOM }}">Feed</a>
 		    &middot;
-		    <a rel="license" href="http://creativecommons.org/licenses/by/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://licensebuttons.net/l/by/4.0/80x15.png" /></a><br />
+		    <a rel="license"
+                href="http://creativecommons.org/licenses/by-nc-nd/4.0/"><img
+                alt="Creative Commons Attribution-NonCommercial-NoDerivatives
+            4.0 International License" style="border-width:0"
+            src="https://mirrors.creativecommons.org/presskit/buttons/80x15/svg/by-nc-nd.svg" /></a><br />
                 </div>
             </div>
             <div class="clear"></div>