Handled-mail should use set issue.assigned_to to the first "To" address
I wanted to be able to send an e-mail "To" a certain person, and CC: the Redmine address, to have Redmine "assign" the resulting new issue to that person. The attached two-line patch to the MailHandler model seems to achieve that, in my limited testing. The assumption with this patch is that Redmine's "role" address is not assigned to a user. If the To: address is not found as a User, no user is assigned.