add hostname and log version to record

log version will increment if record format changes, starting at 1 as we
reach 1.0.0
fix: logger.trace() should not set record.exception
fix for circular references in json output
update console.js for newer dbug
add 'logger' option to console()
add Record and Message classes

`record.message` is now an instanceof Message, and implements toString and
toJSON. This improves how records output when using the JSON format, such that
the args aren't printed as the `args` property, and stringified in the
`message` property. Now, if output is %O (json), the `message` property will
be an array of all the args passed. If `%(message)s` is used, it will still
stringify all the args into a log message.
more changes to changelog