Render occurrences for Event content listing, not events

Generate and render Occurrence instances when listing events within the
event content listing plugin, since the occurrences are what we really
want especially for rendering them in the appropriate order.

icekit_events/plugins/event_content_listing/abstract_models.py

@@ -7,7 +7,7 @@
 
 from timezone import timezone as djtz  # django-timezone
 
-from icekit_events.models import EventType
+from icekit_events.models import EventType, Occurrence
 from icekit.plugins.content_listing.abstract_models import \
     AbstractContentListingItem
 
@@ -54,13 +54,12 @@ def __str__(self):
         return 'Event Content Listing of %s' % self.content_type
 
     def get_items(self):
-        qs = super(AbstractEventContentListingItem, self).get_items(
-            apply_limit=False)
+        qs = Occurrence.objects.visible().distinct()
         if self.limit_to_types.count():
             types = self.limit_to_types.all()
             qs = qs.filter(
-                Q(primary_type__in=types) |
-                Q(secondary_types__in=types)
+                Q(event__primary_type__in=types) |
+                Q(event__secondary_types__in=types)
             )
         # Apply `from_date` and `to_date` limits
         qs = qs.overlapping(self.from_date, self.to_date)
@@ -72,8 +71,6 @@ def get_items(self):
         if self.to_days_ahead is not None:
             to_date = today + timedelta(days=self.to_days_ahead)
         qs = qs.overlapping(from_date, to_date)
-        # Apply a sensible default ordering
-        qs = qs.order_by_first_occurrence()
         if self.limit:
             qs = qs[:self.limit]
         return qs