Added links to .json and .jsono representations

Closes #62

datasette/templates/row.html

@@ -17,6 +17,8 @@
 
 <h1 style="padding-left: 10px; border-left: 10px solid #{{ database_hash[:6] }}">{{ table }}: {{ ', '.join(primary_key_values) }}</a></h1>
 
+<p>This data as <a href="{{ url_json }}">.json</a>, <a href="{{ url_jsono }}">.jsono</a></p>
+
 <table>
     <thead>
         <tr>