JSON Download and Licence in Footer

Addresses okfn#45 Licence. Please confirm single link to PDDL is sufficient
as submission form states data is licensed as both CCZero and/or PDDL

Addresse okfn#33 and okfn#17 JSON API in Site Footer

views/base.html

@@ -69,8 +69,12 @@
     <p>
       This service is run by the <a href="http://okfn.org">Open
         Knowledge Foundation</a>
-      &ndash;
+       |
       <a href="http://github.com/okfn/dataportals.org">Source Code</a>
+       |
+      <a href="http://dataportals.org/api/data.json">Download Data (JSON)</a>
+       |
+      <a href="http://opendatacommons.org/licenses/pddl/1.0">Data License (Public Domain)</a>
     </p>
     <p>
       <a href="http://opendefinition.org/okd/" title="Open Data">