Add a "Withdrawn?" column to proposal lists

pinaxcon/templates/symposion/reviews/_review_table.html

@@ -4,6 +4,7 @@
     <thead>
         <th>#</th>
         <th>{% trans "Speaker / Title" %}</th>
+        <th class="toggle">Withdrawn?</th>
         <th class="toggle">Audience</th>
         <th class="toggle">Format</th>
         <th>{% trans "Votes" %}</th>
@@ -26,6 +27,7 @@
                         {{ proposal.title }}
                     </a>
                 </td>
+                <td>{{ proposal.cancelled }}</td>
                 <td>{{ proposal.get_target_audience_display }}</td>
                 <td>{{ proposal.get_talk_format_display }}</td>
                 <td>{{ proposal.total_votes }}</td>