edit operation format in readme.txt

git-svn-id: https://plugins.svn.wordpress.org/caascade/trunk@962074 b8457f37-d9ea-0310-8a92-e5e31aec5664
edit operation format in readme.txt

git-svn-id: https://plugins.svn.wordpress.org/caascade/trunk@962076 b8457f37-d9ea-0310-8a92-e5e31aec5664