Adding plugin files

git-svn-id: https://plugins.svn.wordpress.org/disable-multisite-rewrites/trunk@873441 b8457f37-d9ea-0310-8a92-e5e31aec5664
Updated readme for latest WordPress version

git-svn-id: https://plugins.svn.wordpress.org/disable-multisite-rewrites/trunk@873442 b8457f37-d9ea-0310-8a92-e5e31aec5664