Added create-event overlay.

Added new-event mark to month-view.
Added navigation arrows to month-view.
Initially moved edit-event to a dialog.

src/gcal-month-view.h

@@ -48,6 +48,9 @@ struct _GcalMonthView
 struct _GcalMonthViewClass
 {
   GtkContainerClass parent_class;
+
+  /* signals */
+  void (*new_event) (gint new_day);
 };
 
 GType          gcal_month_view_get_type         (void);