Use increment operator
Fix SynchronousConsumer not shutting down service

On a fatal error, when configured to do so, the SynchronousConsumer
should shut down the service. However, it was not being registered as a
`ServerListener`.
Fix incorrect Kafka consumer properties

The backported `KafkaConsumerFactory` for 0.7 was configuring some
properties with the incorrect name.
Add TRACE logging for KafkaConsumer shutdown
Add an initial delay to Kafka consumer threads

Consumers will now wait a configurable time (2 seconds, by default)
before starting. This allows the connector to complete any startup tasks
(e.g. re-balancing) before consumption begins.