Removing old readme.txt

git-svn-id: https://plugins.svn.wordpress.org/remove-howdy/trunk@838132 b8457f37-d9ea-0310-8a92-e5e31aec5664
Updated screenshot

git-svn-id: https://plugins.svn.wordpress.org/remove-howdy/trunk@838134 b8457f37-d9ea-0310-8a92-e5e31aec5664
Removing old readme.txt

git-svn-id: https://plugins.svn.wordpress.org/remove-howdy/trunk@838135 b8457f37-d9ea-0310-8a92-e5e31aec5664