Send mails with attachment and multiple receivers

[JornWildt]

It would be useful with a next generation of the mail interface, where both "Ccc" and "Bcc" are supported, as well as multiple addresses for each (using arrays of MailAddress) and attachments.

Attachment would be a list of something like this.

class MailAttachment
{
  string MimeType;
  string Name;
  byte[] Body;
}

In my case I want to send an approval message for a booking to both the tenant as well as a copy to the administrator - with a contract attached.

[purplepiranha]

This is something that I really need.