Freezing

• Freeze water into ice.
• Enclose items in ice to slow spoiling.
• Adjustable ice effectiveness (default 5X slowdown)
• Spoilables do not spoil while inside a powered refrigerator.
• Adds temperatures to planets, fridges draw power based on ambient temperature.
• Wagons, that cool contents like refrigerators, but draw power from equipment grid.
• Dynamic mod support: graphics and spoilage times generated automatically. Modded planets default to 18°C.
• Modders can add surface_properties.temperature (in Celsius) to their planet to change default temperature.