edit readme.txt

git-svn-id: https://plugins.svn.wordpress.org/ez-popup-manager/trunk@753937 b8457f37-d9ea-0310-8a92-e5e31aec5664
Update readme.txt

git-svn-id: https://plugins.svn.wordpress.org/ez-popup-manager/trunk@753938 b8457f37-d9ea-0310-8a92-e5e31aec5664