view: added :event-activated signal

Since the events widget are handled entirely inside GcalView
implementations (aka the views), we need a way to hook event-widget
activation with GcalWindow which is handling the dialogs (as expected).
This signal serve as a bridge between those two objects.

src/gcal-view.c

@@ -52,6 +52,16 @@ gcal_view_base_init (gpointer g_iface)
                     G_TYPE_DOUBLE,
                     G_TYPE_DOUBLE);
 
+      g_signal_new ("event-activated",
+                    GCAL_TYPE_VIEW,
+                    G_SIGNAL_RUN_LAST,
+                    G_STRUCT_OFFSET (GcalViewIface,
+                                     event_activated),
+                    NULL, NULL, NULL,
+                    G_TYPE_NONE,
+                    1,
+                    GCAL_TYPE_EVENT_WIDGET);
+
       initialized = TRUE;
     }
 }

src/gcal-view.h

@@ -46,6 +46,7 @@ struct _GcalViewIface
 
   /* signals */
   void            (*create_event)                       (GcalView *view, icaltimetype *start_span, icaltimetype *end_span, gdouble x, gdouble y);
+  void            (*event_activated)                    (GcalView *view, GcalEventWidget *event_widget);
 
 /* FIXME remove me in favor of the one below */
   void            (*clear_selection)                    (GcalView *view);