Item Storage Modules

In Steve's Carts, storage modules can be built into minecarts in order to store items that the cart collects during operation.

Storage Modules

 * Modular Cost - Defines the cost to add the module to a hull and determines what hulls it can be added to, based on the hull's complexity cap
 * Construction Time - The actual real-time amount required to attach the module to a cart during construction
 * Slots - The number of item slots the storage module can hold