delete old readme

git-svn-id: https://plugins.svn.wordpress.org/socializer/trunk@895851 b8457f37-d9ea-0310-8a92-e5e31aec5664
new readme

git-svn-id: https://plugins.svn.wordpress.org/socializer/trunk@895852 b8457f37-d9ea-0310-8a92-e5e31aec5664