Merge branch 'master' into jgrpp

# Conflicts:
#	cmake/CompileFlags.cmake
#	src/crashlog.cpp
#	src/crashlog.h
#	src/date_type.h
#	src/depot_type.h
#	src/landscape.cpp
#	src/openttd.cpp
#	src/order_cmd.cpp
#	src/order_gui.cpp
#	src/os/macosx/crashlog_osx.cpp
#	src/os/unix/crashlog_unix.cpp
#	src/os/windows/crashlog_win.cpp
#	src/pathfinder/npf/npf.cpp
#	src/road_cmd.cpp
#	src/script/api/script_infrastructure.cpp
#	src/stdafx.h
#	src/table/settings/gui_settings.ini
#	src/table/settings/pathfinding_settings.ini
#	src/tests/CMakeLists.txt

src/engine.cpp

@@ -486,8 +486,7 @@ uint Engine::GetDisplayMaxTractiveEffort() const
  */
 Date Engine::GetLifeLengthInDays() const
 {
-	/* Assume leap years; this gives the player a bit more than the given amount of years, but never less. */
-	return (this->info.lifelength + _settings_game.vehicle.extend_vehicle_life) * DAYS_IN_LEAP_YEAR;
+	return DateAtStartOfYear(this->info.lifelength + _settings_game.vehicle.extend_vehicle_life);
 }
 
 /**
@@ -726,7 +725,7 @@ void SetYearEngineAgingStops()
 
 		/* Base year ending date on half the model life */
 		YearMonthDay ymd;
-		ConvertDateToYMD(ei->base_intro + (ei->lifelength * DAYS_IN_LEAP_YEAR) / 2, &ymd);
+		ConvertDateToYMD(ei->base_intro + DateAtStartOfYear(ei->lifelength) / 2, &ymd);
 
 		_year_engine_aging_stops = std::max(_year_engine_aging_stops, ymd.year);
 	}