release for v4.2.0

git-svn-id: https://plugins.svn.wordpress.org/wp-simple-firewall/trunk@1040338 b8457f37-d9ea-0310-8a92-e5e31aec5664
version bump 4.2.0

git-svn-id: https://plugins.svn.wordpress.org/wp-simple-firewall/trunk@1040340 b8457f37-d9ea-0310-8a92-e5e31aec5664