emails sent by Karl contain broken headers

[Stefan Walluhn]

Karl places mails containing the following headers in the outgoing mail queue:

To: "Example, Dr. Ulrich" <email address hidden> (results in two different mails)

To: =?utf-8?q?Ben_Cowan_=3Cbcowan=40oxfam=2Eorg=2Euk=3E=2CJude_Powell_=3CJP?=
        =?utf-8?q?owell=40oxfam=2Eorg=2Euk=3E=2CVivien_Walden_=3Cvwalden=40o?=
        =?utf-8?q?xfam=2Eorg=2Euk=3E=2CAnne_Leewis_=3Caleewis=40oxfam=2Eorg?=
        =?utf-8?q?=2Euk=3E=2CHassan_Mahmood_=3Chmahmood=40oxfam=2Eorg=2Euk?=
        =?utf-8?b?PixLd29rIExlZSA8a2xlZUBveGZhbS5vcmcudWs+LFN0ZXBoYW5pZSBS?=
        =?utf-8?b?b2JlcnNvbiA8c3JvYmVyc29uQG94ZmFtLm9yZy51az4sTHV6IEfDs21l?=
        =?utf-8?q?z-Saavedra_=3Clgomezs=40intermonoxfam=2Eorg=3E?=
(UTF-8 not allowed in mail headers)

Karl should ensure that an email it passes to the outgoing queue contains RFC valid headers.