spamassassin: workaround for issue #444

and...
    use tests from spamd output (if sent)
    set the contents of a header to '' if undefined
spamassassin: restored empty string test (vs false)
spamassassin: remove hack, insert fix

I think.  So far, so good.
Bump version
Merge pull request #460 from smfreegard/master

Add new -o option to bin/haraka
Update data.headers.js

Removed quotes from 'undefined' in ll. 17/37 to prevent error for non-existing config file.
Merge pull request #462 from pjanotta/patch-1

Update data.headers.js
return after next() in the whitelist checks
Merge pull request #463 from godsflaw/godsflaw

return after next() in the whitelist checks
Merge pull request #464 from smfreegard/master

Prevent plugins adding empty headers
spamassassin: comment out a couple log entries
Merge pull request #445 from msimerson/spamassassin

Merged
tls: increase discoverability and improve docs
Merge pull request #466 from msimerson/tls

Thanks - merged.
Fix #468 - undefined variable