Fix #97 unref() the rotation timeout in RotatingFileStream.

The rotation `setTimeout` from `RotatingFileStream` will prevent the process from exiting.
This fix simply `unref()` the timeout immediately after it is set.
Graceful termination failing test for #97 and #73

Will fail if any timers or callbacks remain registered when
instantiating a logger with a rotating file.
Merge 'chakrit/master' fixing #97 process not exiting
Changelog for 'unref' bugfix #97
fix #105: export addStream and addSerializers
[issue #85] Ensure logging a non-object/non-string doesn't throw
Merge pull request #142 from aexmachina/object-keys-fix

Fix crash from `bunyan` CLI with an `Object.keys called on non-object` message
note aexmachina's change, style tweaks for make check
[issue #139] Fix `bunyan` crash on a log record with `res.header` that is an object.
note express-bunyan-logger project
make check
require check to cut a release
prepare for 0.23.0 release
prep for future dev
dump ver in 'make versioncheck'
Add an example showing how to use raw streams for #130
attempt to clarify error *events*, per #124
Merge pull request #125 from ascom-au/master

Rotating-file stream prevent process from exiting
'make check'
note contributors