Minor changes to readme file and plugin index file

git-svn-id: https://plugins.svn.wordpress.org/wp-twitter-feeds/trunk@936144 b8457f37-d9ea-0310-8a92-e5e31aec5664
Minor changes to readme 

git-svn-id: https://plugins.svn.wordpress.org/wp-twitter-feeds/trunk@936147 b8457f37-d9ea-0310-8a92-e5e31aec5664