replacing ui with ul

git-svn-id: https://plugins.svn.wordpress.org/simple-email-subscriber/trunk@1022905 b8457f37-d9ea-0310-8a92-e5e31aec5664
update 2.3 version tag

git-svn-id: https://plugins.svn.wordpress.org/simple-email-subscriber/trunk@1022910 b8457f37-d9ea-0310-8a92-e5e31aec5664