updated readme

git-svn-id: https://plugins.svn.wordpress.org/si-contact-form/trunk@983345 b8457f37-d9ea-0310-8a92-e5e31aec5664
update readme

git-svn-id: https://plugins.svn.wordpress.org/si-contact-form/trunk@983346 b8457f37-d9ea-0310-8a92-e5e31aec5664