* mark data read from DB (req. for string key where existing key value is not reliable indicator for DB data)
* detect distributors by part of model string
* use a simplified name (no spaces, no special characters) to find a match
* allow to obtain model strings (=keys) as set and list
* do not init shared URLs before needed
* do not load info objects when DB is unavailable
* adjust reader flags when DB is down
* airport URL available in setup
(applied after 1st performance fix for cache was ready)
* utility functions to detect if only caches are used
* renamed some functions
* renamed some db flags and added new ones
