update shortcode file

git-svn-id: https://plugins.svn.wordpress.org/mlr-timeline/trunk@819360 b8457f37-d9ea-0310-8a92-e5e31aec5664
updated class file with options 

git-svn-id: https://plugins.svn.wordpress.org/mlr-timeline/trunk@819362 b8457f37-d9ea-0310-8a92-e5e31aec5664