- Changes to upstream go.enmime help with #20
- Setting content-type is required so that browsers correclty render
docs that don't include an <html> element.
- Removed extra message object from ReadBody() return type
- We now use enmime's GetHeader() when building the GOB, this will get
us alternate character set decoding for the From and Subject headers.
- Added a swaks test with a utf-8 subject line
