deleting the readme

git-svn-id: https://plugins.svn.wordpress.org/subdomain-theme-switch/trunk@1018574 b8457f37-d9ea-0310-8a92-e5e31aec5664
Adding new readme.txt

git-svn-id: https://plugins.svn.wordpress.org/subdomain-theme-switch/trunk@1018575 b8457f37-d9ea-0310-8a92-e5e31aec5664