Added an info parameter to the receive method in order to provide additional info to the carrier. This is needed when receiving messages in MQTT via a specific topic. The topic contains the MQTT username and therefore allows to response to the given user.
Changed interface between carrier and carriermodel in order to pass the additional information further (topic/path).
Changed interface between carrier and carriermodel in order to pass the additional information further (topic/path).
Added MQTT topic prefixes, so that they are configured in a central place.
Extended javadoc. Now, the receive method may throw a CarrierException if anything goes wrong.
Added check for correct topic and convert topic to username.
Test if incoming message is of a valid topic.