Add implementation of multi-aspect signalling and GRF support

Requires realistic braking

See: #247

src/openttd.cpp

@@ -465,6 +465,7 @@ static void ShutdownGame()
 	_game_load_tick_skip_counter = 0;
 	_game_load_time = 0;
 	_extra_station_names_used = 0;
+	_extra_aspects = 0;
 	_loadgame_DBGL_data.clear();
 	_loadgame_DBGC_data.clear();
 }
@@ -1860,6 +1861,7 @@ void StateGameLoop()
 			UpdateStateChecksum(c->money);
 		}
 	}
+	if (_extra_aspects > 0) FlushDeferredAspectUpdates();
 
 	assert(IsLocalCompany());
 }