Make sure bunyan-raven works properly with Bunyan's err serialization
When no error is given to Bunyan logger, a Raven#captureMessage is used instead
Adding name, hostname, pid and level as Raven tags
Safe converting additional custom Bunyan attributes to Raven extra fields
Making error and messages play well together
Added to examples and bumped version
Changed version to 0.2.0
Merge pull request #2 from dominiek/master

Several fixes and tweaks