0.9.0

• 226:
  Better failsafe when announcement is not supported by Servus
• 225:
  Fix #224: Handle exceptions in server handlers
• 219:
  Implement Client-Server req-rep support
  • The environment variables ZEROEQ_PUB_SESSION and ZEROEQ_SERVER_SESSION
    replace the now deprecated ZEROEQ_SESSION variable.
• 223:
  Subscriber(uri) ctors are replaced by Subscriber(uris)
• 218:
  Fix infinite loop in slow receivers
• 215:
  Implement Monitor to receive notifications for new subscribers
• 217:
  Fix HTTP server response to CORS requests ("Access-Control-Allow-Origin: *"
  was missing).
• 216:
  http::Server can be subclassed to filter requests, which can be useful to
  restrict access to selected hosts or methods.
• 213:
  Remove ambiguous Subscriber(uri, session) ctors