Updating to version 1.5.0.

git-svn-id: https://plugins.svn.wordpress.org/zero-spam/trunk@1008063 b8457f37-d9ea-0310-8a92-e5e31aec5664
Preparing for 1.5.0 release

git-svn-id: https://plugins.svn.wordpress.org/zero-spam/trunk@1008067 b8457f37-d9ea-0310-8a92-e5e31aec5664