Converted GcalMonthView to GtkContainer subclass.

Added gcal_view_add_event method GcalView interface.
Fixed size_allocate implementation in GcalMonthView to allocate children events.

There's still work to be done here.

src/gcal-view.h

@@ -21,6 +21,7 @@
 #define __GCAL_VIEW_H__
 
 #include <glib-object.h>
+#include <gtk/gtk.h>
 
 #include <libical/icaltime.h>
 
@@ -39,12 +40,17 @@ struct _GcalViewIface
 {
   GTypeInterface parent_iface;
 
-  gboolean (*is_in_range) (GcalView *view, icaltimetype* date);
+  gboolean (*is_in_range) (GcalView *view, icaltimetype *date);
+  void     (*add_event)   (GcalView *view, GtkWidget    *event);
 };
 
 GType  gcal_view_get_type  (void);
 
-gboolean gcal_view_is_in_range (GcalView *view, icaltimetype* date);
+gboolean gcal_view_is_in_range (GcalView     *view,
+                                icaltimetype *date);
+
+void     gcal_view_add_event   (GcalView     *view,
+                                GtkWidget    *event);
 
 G_END_DECLS