Reconnect the jms-connections

When an jms-exception is thrown the current message-bus connection (ActiveMQConnection) dies and cannot be reused.
It should instead make a number of retries (perhaps 3?) to reestablish the connection before it gives up. Then the connection should be closed, but it should be possible to try to reestablish the connection again at a later time.

This is not a critical feature in the prototype.