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/simulation/distributor.cpp

@@ -178,6 +178,7 @@ namespace BlackMisc
             Q_ASSERT_X(!description.isEmpty(), Q_FUNC_INFO, "Missing description");
             CDistributor distributor("", description, alias1, alias2, simulator);
             distributor.setKeyAndTimestampFromDatabaseJson(json, prefix);
+            distributor.setLoadedFromDb(true);
             return distributor;
         }
     } // namespace