Does not always correctly detect and decode quoted-printable

[rpkamp]

Example:

$message = (new Swift_Message())
    ->setFrom('me@myself.example', 'Myself')
    ->setTo('me@myself.example')
    ->setBody('Check out this Behat extension for MailHog on <a href="https://github.com/rpkamp/mailhog-behat-context">github</a>.')
    ->setSubject('Mailhog extension for Behat');

$mailer = new Swift_Mailer(new Swift_SmtpTransport('localhost', 3025));

$mailer->send($message);

body will not be decoded before returned.