Marked 2.3.4 as stable.

git-svn-id: https://plugins.svn.wordpress.org/fetch-tweets/trunk@914273 b8457f37-d9ea-0310-8a92-e5e31aec5664
Updating readme since the tags are not reflected in the plugin front page.

git-svn-id: https://plugins.svn.wordpress.org/fetch-tweets/trunk@914277 b8457f37-d9ea-0310-8a92-e5e31aec5664