Added capturing group to match email addresses of type John Doe <firstname.lastname@example.org> correctly.
The existing regex to match mail addresses – (?:<)[^>]*(?:>) – does not have a capturing group and would therefore match
<email@example.com>, which is not a valid email address. This leads to the problem that using the full name in the reply-to field always fails. The patch introduces a capturing group, now only
firstname.lastname@example.org is checked for email address validity.