updated core patch to fix merge conflicts with current trunk, remove post by email options from sanitize_option, and add _doing_it_wrong to wp-mail.php.

git-svn-id: http://gsoc.svn.wordpress.org/2013/codebykat/post-by-email/trunk@2327 f69abe3c-2ee2-4550-9a6d-17bd458115be