Major upgrade - version 3.0.0

git-svn-id: https://plugins.svn.wordpress.org/page-expiration-robot/trunk@1008905 b8457f37-d9ea-0310-8a92-e5e31aec5664
Fixing readme.

git-svn-id: https://plugins.svn.wordpress.org/page-expiration-robot/trunk@1008906 b8457f37-d9ea-0310-8a92-e5e31aec5664