Feature #457

- Tasks may now be given an 'until' date, after which they expire and are
  deleted.

src/feedback.cpp

@@ -468,6 +468,18 @@ std::string onProjectChange (Task& task1, Task& task2)
   return messages;
 }
 
+///////////////////////////////////////////////////////////////////////////////
+std::string onExpiration (Task& task)
+{
+  std::stringstream msg;
+
+  if (context.verbose ("affected"))
+    msg << format (STRING_FEEDBACK_EXPIRED, task.id, task.get ("description"))
+        << "\n";
+
+  return msg.str ();
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 static void countTasks (
   const std::vector <Task>& all,