added a check and send download only on payment

git-svn-id: https://plugins.svn.wordpress.org/orbisius-cyberstore/trunk@835802 b8457f37-d9ea-0310-8a92-e5e31aec5664
updated readme

git-svn-id: https://plugins.svn.wordpress.org/orbisius-cyberstore/trunk@835803 b8457f37-d9ea-0310-8a92-e5e31aec5664