Don't send out multiple emails to the same email address.

[nick.grimshaw@…]

If a user appears as either reporter or assigned-to (assuming the relevant always_notify_* is turned on) and in the CC list for a given ticket, then they receive multiple notification emails.

One of them seems to be sent directly to that user alone, one sent to all of the users on the CC list. If it's relevant, we use our email addresses as user names.

Ideally, any given email address should receive at-most-one notification email.

[eblot]

This issue should have been fixed in 0.10: duplicate email addresses are removed from the recipient list before the email is sent to the SMTP server.