Update Readme File

git-svn-id: https://plugins.svn.wordpress.org/wp-bbcode/trunk@859308 b8457f37-d9ea-0310-8a92-e5e31aec5664
Add Plugin Language Text Domain Information

git-svn-id: https://plugins.svn.wordpress.org/wp-bbcode/trunk@860061 b8457f37-d9ea-0310-8a92-e5e31aec5664