Add Mailchimp unsubscribe note to tab info at contact level.

When a contact unsubscribes from a mailchimp campaign although the 'unsubscribe flag' is switched, when you look at the mailchimp tab at contact level it appears thre is nothing to reflect this such as with 'bounced'. It would be useful to see on there that the customer has unsubscribed or even that the email has been successfully delivered. You have to view marketing campaigns.