Fix the rest of issue #1 and some other stuff

We now handle the following exceptions when parsing headers:

  * "UnicodeEncodeError: 'utf-8' codec can't encode character '\udcf8'
    in position 64: surrogates not allowed (also from absorb_headers()"

  * "email.errors.HeaderParseError: expected ':' at end of group
    display name but found '@GMAIL.COM"

    (which would then lead to "TypeError: 'ValueTerminal' object does
    not support item assignment")

  * "ValueError: hour must be in 0..23" (from bogus Date headers)

Also:

  * Solve a newly-discovered quoting problem in the output

  * Ingest 'reply-to' as an address-containing header.