allow EOF after logout
Allow directly adjacent encoded words.

Although they are violating RFC 2047:

>   Ordinary ASCII text and 'encoded-word's may appear together in the
>   same header field.  However, an 'encoded-word' that appears in a
>   header field defined as '*text' MUST be separated from any adjacent
>   'encoded-word' or 'text' by 'linear-white-space'.

(5. Use of encoded-words in message headers,
    http://tools.ietf.org/html/rfc2047#section-5)

And of course, adjacent encoded words don't really make any sense.

On the other hand one can apply the [robustness principle][1] here:

> Be conservative in what you do, be liberal in what you accept from others

(John Postel, RFC 761, https://tools.ietf.org/html/rfc761#section-2.10)

[1]: http://en.wikipedia.org/wiki/Robustness_principle#cite_note-1