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- Fixed `Message-Id` handling (see http://bugs.repoze.org/issue177).
- Provided improved support for encoding messages to bytes. It should now be
possible to represent your messages in `email.message.Message` objects just
with unicode (excepting bytes for binary attachments) and the mailer will
handler it as appropriate.
- Added tests for cPython 2.5, 2.6, 2.7, 3.2, jython 2.5 and pypy 1.8
compatibility.