initial code import

git-svn-id: https://plugins.svn.wordpress.org/nginx-cache/trunk@1029092 b8457f37-d9ea-0310-8a92-e5e31aec5664
added `.pot` file

git-svn-id: https://plugins.svn.wordpress.org/nginx-cache/trunk@1029093 b8457f37-d9ea-0310-8a92-e5e31aec5664