fix text

git-svn-id: https://plugins.svn.wordpress.org/ig-shortcodes/trunk@945044 b8457f37-d9ea-0310-8a92-e5e31aec5664
new readme

git-svn-id: https://plugins.svn.wordpress.org/ig-shortcodes/trunk@945047 b8457f37-d9ea-0310-8a92-e5e31aec5664