[#10][HOTFIX] Handle listid new (proper) format, and fix delivered-to formats

Closes #10 (closed) Follows enabling editHeader plugin on Dovecot and adding in all 3 mailboxes the sieve rule:

require ["envelope", "editheader", "variables"];
# rule:[add-deliveredto]
if allof (not exists "Delivered-To",
        envelope :matches :all "To" "*") {
    addheader "Delivered-To" "${1}";
    keep;
}