1.2.0 - Retry with backoff strategy

Allow jobs to only retry a certain amount of times.
Back off either a fixed number of seconds or an exponentially increasing number of seconds, depending on configuration.

The poll command used to retry failed jobs immediately right after the current batch was finished and kept on retrying indefinitely.
For compatibility reasons, that's still the behavior, which is achieved by a numberOfRetries of -1, a backoffStrategy set to "linear" and a retryInterval of 0.