By Jessica Firger and Hannah Fraser-Chanpong CBSNews.com May 15, 2014, 7:59 PM Visit to 9/11 museum may be cathartic for some; traumatic for others   Links/Video: http://www.cbsnews.com/news/visit-to-911-museum-may-be-cathartic-for-some-too-traumatic-for-others/ http://www.911memorial.org/   Obama, 9/11 families, first responders attend museum memorial dedication By Ray...