refs #538, Formatting, minor tweaks, comments

* new slot syntax in ATC station component
* formatting, comments
* tab order
* utility function for severity in status message
* null checks in threadutils
* invalidKey function in datastore
* changed data object keys (cached objets)
* added missing value object compare cases
* renamed timer in context network
* finder function for model list
* renamed getContainer to container (as it is just a reference)

src/blackmisc/aviation/airlineicaocode.cpp

@@ -166,6 +166,8 @@ namespace BlackMisc
                 return this->m_designator.compare(compareValue.getDesignator());
             case IndexAirlineCountry:
                 return this->m_country.comparePropertyByIndex(compareValue.getCountry(), index.copyFrontRemoved());
+            case IndexDesignatorNameCountry:
+                return this->m_country.getName().compare(compareValue.getCountry().getName(), Qt::CaseInsensitive);
             case IndexAirlineName:
                 return this->m_name.compare(compareValue.getName(), Qt::CaseInsensitive);
             case IndexTelephonyDesignator: