Gazetteer for landscape features

It should be possible to add labels for geographic features visible along the horizon.
GUI should have a switch (and maybe hotkey) "name horizon features", and it should be possible to configure font size&color at least via config.ini.
It should be enough to enable all names at once. Features should be listed in a file gazetteer.<LANGUAGE>.ini, with entries for azimuth,altitude,offset-for-label,name.