bugfixes + screenshot menu + change int values with float

git-svn-id: https://plugins.svn.wordpress.org/jm-dashicons-shortcode/trunk@854343 b8457f37-d9ea-0310-8a92-e5e31aec5664
update readme.txt

git-svn-id: https://plugins.svn.wordpress.org/jm-dashicons-shortcode/trunk@854353 b8457f37-d9ea-0310-8a92-e5e31aec5664