Remove the personalised bits of session chair display

- The schedule grid page is ridculously database-query heavy and hence
  terribly lacking in perfmantitude.
- Caching can help with this, but the caching implemention at present
  is not user-aware. If one user looks at the page, they'll get a
  "YOU" in all the places they're chair and something else everywhere
  else - and then everyone will see that for the next 600 seconds,
  then YOU will become someone else
- to avoid this, remove the request.user-specific bit of the template

pinaxcon/templates/symposion/schedule/_grid.html

@@ -16,7 +16,7 @@
           {% for room in timetable.rooms %}
             {% with room|trackname:timetable.day as track_name %}
               <th class="track-name">{% if track_name %}<p>{{ track_name }}{% endif %}</th>
-            {% endwith %}
+	        {% endwith %}
           {% endfor %}
         </tr>
       {% endif %}
@@ -44,8 +44,6 @@
                         <em>Session chair:
                         {% if not session.chair %}
                           <a href="{% url "schedule_session_detail" session.id %}">Volunteer! 🙋</a>
-                        {% elif session.chair.user == request.user %}
-                          <a href="{% url "schedule_session_detail" session.id %}"><strong>You!</strong></a>
                         {% endif %}</em>
                       {% endfor %}
                     </div>