Add support for embedded images.
Set character encoding to a non-base64 version so allow 'view source' to work better in email clients.
Add support for CC and BCC.
Add import for email.charset.
Add suppport for setting the SMTP connection timeout.
Remove default reference to smtp.gmail.com.
Merge branch 'feature/embedded_images' into develop
Merge branch 'feature/cc_bcc_support' into develop
Merge branch 'feature/timeout_support' into develop