Make PLAIN AUTH SMTP work with long username/passwords.

[cstorey]

As it stands, the smtpclient protocol uses Array#pack to base64 encode data, which wraps the output at 60-characters (as you would when sending base64-encoded mail). However, the AUTH SMTP extension expects the initial authentication string to be a single line.

This is a particular issue when using credentials for Amazon's simple email service, which tend to be quite long (>64 characters combined).

Is this okay to be merged as is, or is there anything else you'd need me to do first?

[ibc]

It's much better to use Base64::strict_encode64 which does not add \n.

[ibc]

Unfortunately Base64::strict_encode64 does not exist in Ruby 1.8.

[cstorey]

Thanks!