- added experimental ZMQ messaging functionality to ControlUnit.cpp. CarStatus updates will be published
- added getCarStatusMessage to CarStatus to be able to pass ProtoBuf for serialization
- added sendCarStatusMessage / sendTrackStatusMessage to ControlUnit that use ZMQ for sending the messages
- added ZMQ flags / parameters to makefile
- cleaned up SlotHub.c to just initialize and start a ControlUnit object for testing
- moved inPit attribute to ProtoBuf member