tweaked text on read me

git-svn-id: https://plugins.svn.wordpress.org/tabby-responsive-tabs/trunk@947005 b8457f37-d9ea-0310-8a92-e5e31aec5664
tweaked text on read me

git-svn-id: https://plugins.svn.wordpress.org/tabby-responsive-tabs/trunk@947010 b8457f37-d9ea-0310-8a92-e5e31aec5664