ALF-10318 Update CalendarEntry to hold the created and modified at dates

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@30601 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/service/cmr/calendar/CalendarEntry.java

@@ -159,4 +159,14 @@ public interface CalendarEntry extends Serializable, PermissionCheckValue
     * @return the Tags associated with the event 
     */
    List<String> getTags();
+   
+   /**
+    * @return the creation date and time
+    */
+   Date getCreatedAt();
+   
+   /**
+    * @return the modification date and time
+    */
+   Date getModifiedAt();
 }