update readme, set for adoption

git-svn-id: https://plugins.svn.wordpress.org/flot/trunk@951515 b8457f37-d9ea-0310-8a92-e5e31aec5664
minor code improvement

git-svn-id: https://plugins.svn.wordpress.org/flot/trunk@951516 b8457f37-d9ea-0310-8a92-e5e31aec5664