Broadcast data from GPredict for other Ham Radio Applications

Description of the project: add code to GPredict so that it can broadcast real-time data about satellite visibility, location and doppler shift to other applications using messaging solutions such as D-Bus and Apache Qpid or other asynchronous messaging solutions based on protocols like AMQP. Example use cases for this project: an SDR application like gqrx might use the doppler shift information to adjust the VFO in real-time, a Raspberry Pi attached to an antenna rotator might run an application to receive data from Apache Qpid and move the antenna or dish.