Added support for internationalization.

git-svn-id: https://plugins.svn.wordpress.org/book-review/trunk@786970 b8457f37-d9ea-0310-8a92-e5e31aec5664
Added pot file.

git-svn-id: https://plugins.svn.wordpress.org/book-review/trunk@786971 b8457f37-d9ea-0310-8a92-e5e31aec5664
Added Italian translation files.

git-svn-id: https://plugins.svn.wordpress.org/book-review/trunk@788136 b8457f37-d9ea-0310-8a92-e5e31aec5664