add MAIL_ASCII_ATTACHMENTS, to force ascii filenames for attachments
document MAIL_ASCII_ATTACHMENTS
fix for python 2.6 support
py2.6 compat: number placeholders in string.format
Fix issue sending unicode messages in Python 3

Connection.send() now uses email.message.Message.as_bytes() in Python 3, and email.message.Message.as_string() in Python 2.
Add fallback to Message.as_bytes() for Python 3 < 3.4
Merge pull request #85 from lyschoening/py3-unicode

Fix #64 send unicode messages in Python 3
ascii_attachments: don't process filename's extension apart
more doc about MAIL_ASCII_ATTACHMENTS
Merge pull request #84 from bmathieu33/ascii_filenames

Ascii filenames