view iface: remove unused will_add_event

ECalDataModelSubscriber interface notify each view only about the events
beloging to the subscribed range so there's no need of checking if the
event widget will be added.
The safety check of not adding the same widget twice its stil being made
on each GtkContainer::add implementation.

src/gcal-week-view.c

@@ -156,9 +156,6 @@ static gboolean       gcal_week_view_draw_event            (GcalView       *view
 static GtkWidget*     gcal_week_view_get_by_uuid           (GcalView       *view,
                                                             const gchar    *uuid);
 
-static gboolean       gcal_week_view_will_add_event        (GcalView        *view,
-                                                            GcalEventWidget *event);
-
 G_DEFINE_TYPE_WITH_CODE (GcalWeekView,
                          gcal_week_view,
                          GTK_TYPE_CONTAINER,
@@ -236,8 +233,6 @@ gcal_view_interface_init (GcalViewIface *iface)
   iface->draw_event = gcal_week_view_draw_event;
   iface->get_by_uuid = gcal_week_view_get_by_uuid;
   /* iface->clear = gcal_week_view_clear; */
-
-  iface->will_add_event = gcal_week_view_will_add_event;
 }
 
 static void
@@ -1418,13 +1413,6 @@ gcal_week_view_get_by_uuid (GcalView    *view,
   return NULL;
 }
 
-static gboolean
-gcal_week_view_will_add_event (GcalView        *view,
-                               GcalEventWidget *event)
-{
-  ;
-}
-
 /* Public API */
 /**
  * gcal_week_view_new: