Release 0.0.3

Changes in this release

• Do not start if gateway IP cannot be determined
• Do not start if a dependency is non-existent
• systemd-service: run srd after network-online.target
• configure num_pings (number of pings sent)
• add configuration 'run_if' to actions to define when it is run
  • down, up, always, up-again
• print latency in command with %lat_ms