merges Digitalshift/MailboxAbstractionBundle and Digitalshift/MailboxConnectionBundle (#9), refactores Message, MessageHeaders & MessageMimePart into MimeMessage, MimeMessageHeaders & MimeMessagePart (#10)
Merge pull request #11 from soeren-helbig/0.1.x

merges Digitalshift/MailboxAbstractionBundle and Digitalshift/MailboxCon...