Changed the version to 2.1.1.

git-svn-id: https://plugins.svn.wordpress.org/fetch-tweets/trunk@881196 b8457f37-d9ea-0310-8a92-e5e31aec5664
Marked 2.1.1 as stable.

git-svn-id: https://plugins.svn.wordpress.org/fetch-tweets/trunk@881199 b8457f37-d9ea-0310-8a92-e5e31aec5664