* in case the internet provider is down, this is not detected
* extended test to detect if access is possible
* in case of downtime this indicated in status component
* Log when VATSIM status file has been read
* fix: read VATSIM status file after initReaders completes
* some private slots -> normal private functions
* removed copy/paste error illegalIcaoCodes
follow up of Ref T105
* use doWorkCheck
* relaxed doWorkCheck in unit tests
* removed isShuttingDown, gracefulShutdown
* set timer object name (in case something is wrong, we might see the name in the log)
* new read state "skipped"
* renamed to "isNetworkConnectedAndAccessible"
* checking before reading, which would only fail if network is not accessible