full title......................Obama says he is 'cautiously optimistic' about Trump's presidency but warns him he 'probably won't be there very long' if he doesn't take the job seriously - and refuses to call for an end to protests............................. Obama said Trump will find out 'fairly quickly' that he can't take his new role 'casually' and that he must listen and reach out to a variety of groups if he wants to see success 'If you're not serious about the job, then you probably won't be there very long because it will expose problems,' he said at a news conference today in...