v1.3 - download links and embed non-Google file types

git-svn-id: https://plugins.svn.wordpress.org/google-drive-embedder/trunk@863120 b8457f37-d9ea-0310-8a92-e5e31aec5664
changed links in readme

git-svn-id: https://plugins.svn.wordpress.org/google-drive-embedder/trunk@869329 b8457f37-d9ea-0310-8a92-e5e31aec5664