readme.txt update

git-svn-id: https://plugins.svn.wordpress.org/kento-post-view-counter/trunk@856056 b8457f37-d9ea-0310-8a92-e5e31aec5664
readme.txt update

git-svn-id: https://plugins.svn.wordpress.org/kento-post-view-counter/trunk@856938 b8457f37-d9ea-0310-8a92-e5e31aec5664
update readme.txt for 1.9

git-svn-id: https://plugins.svn.wordpress.org/kento-post-view-counter/trunk@858267 b8457f37-d9ea-0310-8a92-e5e31aec5664