caused by matching on hostname, e.g. Linux on a Mac

and improvements, and a couple light theme fixes too

- Flush output to fix truncated mails
- Close output for attachments
- Fix setting encoding for attachments
- Set length for binary encoding

previously unsupported, same as 8bit, ref: RFC 2045

They were copies of "first", not reverses of "next"

Fix handing of multiple IGDs
Improve logging about multiple IGDs
Add info on UPnP tab on how to disable an IGD
Log tweaks