Don't encode email subject if not necessary.

[colinmollenhour]

A couple reasons:

1. It makes it hard to read when debugging, or if viewing the raw email headers, or in some client that is not smart enough to decode the subject (yes, there are a few).
2. I've seen a spamassassin rule that dings an email if the subject is unnecessarily encoded.

So the solution would be to use a method to detect if the subject has non-ascii characters and not encode it if it doesn't.

[magento-team]

@colinmollenhour
Message subject is encoded in accordance with the RFC 2047 section 5 "Use of encoded-words in message headers":

An 'encoded-word' may appear in a message header or body part header
according to the following rules:

(1) An 'encoded-word' may replace a 'text' token (as defined by RFC 822)
in any Subject or Comments header field, any extension message
header field, or any MIME body part field for which the field body
is defined as '*text'.

SpamAssassin rule, which dings an email if the subject is unnecessarily encoded, does not comply with the RFC 2047 section 6.1 "Recognition of 'encoded-word's in message headers".

It's essential for debugging to access data "as is", whether it's encoded or not.

Closing the ticket as "won't fix".