updated plugin authentication system

git-svn-id: https://plugins.svn.wordpress.org/landing-pages-builder/trunk@869569 b8457f37-d9ea-0310-8a92-e5e31aec5664
added another tag for better indexing

git-svn-id: https://plugins.svn.wordpress.org/landing-pages-builder/trunk@869577 b8457f37-d9ea-0310-8a92-e5e31aec5664