sackmotion/motion — pull request #19 by torao (2014-04-18 21:29:00+00:00)
Title: remove redundant prefix -- from boundary

The boundary string that separates each message-parts is same as one in Content-Type header.
According to RFC, the boundary as message-part separator must be prefixed "--".
http://www.w3.org/Protocols/rfc1341/7_2_Multipart.html
In this reason some browser such as Chrome are not work well.