new plugin: rcpt_to.qmail_deliverable
qmd: code quality improvements

removed no-longer-needed breaks
changed error message for unknown QMD::Client error
pass this, so error messages log with plugin name
qmd: url escape email address
qmd: move res.setEncoding before data
added docs for qmail_deliverable plugin
qmd: log entries have connection UUID and

config fetching moved inside the rcpt_to hook
Merge pull request #399 from msimerson/qmd

new plugin: rcpt_to.qmail_deliverable