2.9.0

• Added get_offered_services_async method to application interface to
  read the currently offered services
• Added set_watchdog_handler method to application interface which can
  be used to register a handler invoked in a given interval.
• Optimize processing time of incoming service discovery messages
• Events are now sent based on their configuration in the json file
• If a remote service is offered reliable and unreliable subscriptions
  are now done always with both endpoint options.
• Incoming subscriptions are now not acknowledged if not all events of
  the eventgroup can be served with the given endpoint options.