refs #720, improved distributor and airline/livery detection

* 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

src/blackmisc/country.h

@@ -149,7 +149,8 @@ namespace BlackMisc
 
         BLACK_METACLASS(
             CCountry,
-            BLACK_METAMEMBER(dbKey),
+            BLACK_METAMEMBER(dbKey, 0, CaseInsensitiveComparison),
+            BLACK_METAMEMBER(loadedFromDb),
             BLACK_METAMEMBER(timestampMSecsSinceEpoch),
             BLACK_METAMEMBER(iso3),
             BLACK_METAMEMBER(name),