Improved Kafak Error Handling

1) In the event of an exception in the SynchronousConsumer the time
   between retries increases exponentially, with a ceiling.
2) If the number of exceptions exceeds a configurable maximum within
   a time window, the consumer transitions to a unrecoverable state.
3) If an unrecoverable error has occurred, the SynchronousConsumer can
   optionally trigger a graceful shutdown of the Jetty Server.
Update coding style and rename config params

Bring it in line with the rest of the project and use names that are
less likely to incite a murderous rage in people writing config files.
Some more minor tweaks
[maven-release-plugin] prepare release dropwizard-extra-0.6.2-3