update readme.txt

git-svn-id: https://plugins.svn.wordpress.org/custom-preloader/trunk@1042041 b8457f37-d9ea-0310-8a92-e5e31aec5664
update

git-svn-id: https://plugins.svn.wordpress.org/custom-preloader/trunk@1042043 b8457f37-d9ea-0310-8a92-e5e31aec5664