updated readme file

git-svn-id: https://plugins.svn.wordpress.org/google-map-locations/trunk@775975 b8457f37-d9ea-0310-8a92-e5e31aec5664
Updated readme file 2

git-svn-id: https://plugins.svn.wordpress.org/google-map-locations/trunk@775976 b8457f37-d9ea-0310-8a92-e5e31aec5664