Prep for v4.5.3 release.

git-svn-id: https://plugins.svn.wordpress.org/email-users/trunk@783691 b8457f37-d9ea-0310-8a92-e5e31aec5664
Prep for v4.5.4 release.

git-svn-id: https://plugins.svn.wordpress.org/email-users/trunk@783693 b8457f37-d9ea-0310-8a92-e5e31aec5664
Forgot to register settings for new X-Mailer and MIME-Type options.

git-svn-id: https://plugins.svn.wordpress.org/email-users/trunk@784271 b8457f37-d9ea-0310-8a92-e5e31aec5664
Prep for v4.5.5 release.

git-svn-id: https://plugins.svn.wordpress.org/email-users/trunk@784272 b8457f37-d9ea-0310-8a92-e5e31aec5664
Prep for v4.5.5 release.

git-svn-id: https://plugins.svn.wordpress.org/email-users/trunk@784273 b8457f37-d9ea-0310-8a92-e5e31aec5664