view: Remove first weekday helpers when unecessary

Not all views need to know the first weekday, and those
who need, it can be stored internally.

src/views/gcal-week-grid.c

@@ -49,11 +49,8 @@ struct _GcalWeekGrid
   GtkContainer        parent;
 
   GtkWidget          *hours_sidebar;
-
   GdkWindow          *event_window;
 
-  gint                first_weekday;
-
   icaltimetype       *active_date;
 
   GcalRangeTree      *events;
@@ -1144,15 +1141,6 @@ gcal_week_grid_set_manager (GcalWeekGrid *self,
                             self);
 }
 
-void
-gcal_week_grid_set_first_weekday (GcalWeekGrid *self,
-                                  gint          nr_day)
-{
-  g_return_if_fail (GCAL_IS_WEEK_GRID (self));
-
-  self->first_weekday = nr_day;
-}
-
 void
 gcal_week_grid_add_event (GcalWeekGrid *self,
                           GcalEvent    *event)