manager: migrate :objects-added signal

GcalManager:objects-added signal pass a list of struct containing
ECalComponents for the event widgets. This ECalComponent instance will
be owned and released by the event widget. Look at: GcalEventWidget::finalize

src/gcal-manager.h

@@ -23,6 +23,9 @@
 #include <gtk/gtk.h>
 #include <glib-object.h>
 
+#include <libedataserver/libedataserver.h>
+#include <libecal/libecal.h>
+
 #include <libical/icaltime.h>
 
 G_BEGIN_DECLS
@@ -54,6 +57,12 @@ struct _GcalManagerClass
 
 };
 
+typedef struct
+{
+  ESource       *source;
+  ECalComponent *event_component;
+} GcalEventData;
+
 GType          gcal_manager_get_type                (void);
 
 GcalManager*   gcal_manager_new                     (void);