Also sort film/music/attendee events

Otherwise they end up in the order they were in the schedule, which is just
sorted by ID, so isn't very helpful, since it isn't chronological or by name.

apps/schedule/historic.py

@@ -103,7 +103,10 @@ def sort_key(event):
     stage_events.sort(key=sort_key)
     workshop_events.sort(key=sort_key)
     youth_events.sort(key=sort_key)
+    film_events.sort(key=sort_key)
+    music_events.sort(key=sort_key)
     performance_events.sort(key=sort_key)
+    attendee_events.sort(key=sort_key)
 
     venues = [
         {"name": "Main Stages", "events": stage_events},