Event handling

• Extend client::ViewSelection to handle several events, e.g., the requested target being scheduled

This should be inspired by the navigation package, in particular client/services/MemorySubscriber. See also examples/components/example_client/Component.cpp:

  armarx::navigation::client::StopEvent se = getNavigator().waitForStop();
 if (se)
        {
            ARMARX_INFO << "Goal 1 reached.";
        }
        else
        {
            if (se.isSafetyStopTriggeredEvent())
            {
                ARMARX_ERROR << "Safety stop was triggered!";
            }
            else if (se.isUserAbortTriggeredEvent())
            {
                ARMARX_ERROR << "Aborted by user!";
            }
            else if (se.isInternalErrorEvent())
            {
                ARMARX_ERROR << "Unknown internal error occured! "
                             << se.toInternalErrorEvent().message;
            }
        }