Add proper time zone support

Until now event timestamps were saved in the server’s time zone.  Now they are saved in UTC,
considering the time zone set by the creator of the event.

calsocial/templates/month-view.html

@@ -6,6 +6,7 @@
  table.calendar {
      width: 100%;
      border-collapse: collapse;
+     table-layout: fixed;
  }
 
  tr.month > td {
@@ -46,14 +47,31 @@
      background-color: #d8d8d8;
  }
 
- td > div.event {
+ tr.week > td > div.event {
      border: 1px solid green;
      background-color: white;
      border-radius: 2px;
+     text-overflow: ellipsis;
+     white-space: nowrap;
+     overflow: hidden;
+ }
+
+ tr.sizer > td {
+     width: 14.2857%;
+     height: 0;
  }
 </style>
 <table class="calendar">
     <thead>
+        <tr class="sizer">
+            <td></td>
+            <td></td>
+            <td></td>
+            <td></td>
+            <td></td>
+            <td></td>
+            <td></td>
+        </tr>
         <tr class="month">
             <td>
                 <a href="{{ url_for('hello', date=calendar.prev_year) }}">« {{ calendar.prev_year_year }}</a>
@@ -101,6 +119,8 @@
                 <span class="day-num">{{ day.day }}</span>
     {% for event in calendar.day_events(day, user=current_user) %}
                 <div class="event">
+                    {{ event.start_time_tz.strftime('%H:%M') }}–{{ event.end_time_tz.strftime('%H:%M') }}
+                    ({{ event.time_zone }})
                     {{ event.title }}
                 </div>
     {% endfor %}