Inventory terms and definitions.

InventoryItem:
    name
                - Default = required so nothing.
                - Standard length used most places.

    description
                - Default = "".     
                - Longer for additional info only shown in detail views.

    isActive    
                - Default=true, false if "Trashed".
                - Set false by Trash action.
                - Set true by Restore action. 
                - Require true when creating new entries/lists for dropdowns etc.
                - Ignore when viewing old associations or creating lists for searching etc.

    isObsolete    
                - Default=false.
                - Is this InventoryItem now considered obsolete by the manufacturer.

    manufacturersPartNumber
                - Default = "".     
                - The part number that the manufacturer uses to identify this InventoryItem.

    suppliersPartNumber
                - Default = "".     
                - The part number that the supplier uses to identify this InventoryItem.

    enableReorder    
                - Default=true.
                - Should this InventoryItem appear on reorder and auto order lists.

    reorderPoint
                - Required so no default.
                - Once total StoredItems equals this point the item will appear on reorder and auto order lists.

    recommendedReorderPoint
                - Provided the required information is available a recommendedReorderPoint is calculated.

    averageDeliveryTime
                - The average delivery time in days from placement of reorder.

   inventoryGroup
                - Default = required so nothing.
                - The InventoryGroup this InventoryItem belongs to.
                - Initially one of "Misc", "Mechanical", "Electrical", "Production", "Raw Materials".
                - Of Class InventoryGroup.

    inventoryType
                - Default = required so nothing.
                - Initially one of "Consumable", "Repairable".
                - Of Class InventoryType.

    unitOfMeasure
                - Default = required so nothing.
                - Initially one of "each", "meter(s)", "box(es)", "litre(s)"
                - Of Class UnitOfMeasure.

    alternateItems
                - An InventoryItem may have many alternateItems of Class InventoryItem.
                - Indicates that this InventoryItem has alternatives.

    spareFor
                - An InventoryItem may have many assets that it is a spare for, of Class Asset.

    storedItems
                - An InventoryItem may have many StoredItems of Class StoredItem.

    inventoryMovements
                - An InventoryItem may have many InventoryMovements of Class InventoryMovement.

    manufacturers
                - An InventoryItem may have many Manufacturers of the Class Manufacturer.

    suppliers
               - An InventoryItem may have many Suppliers of the Class Supplier.


#External required actions.
Calculate/Show total storedItems.

InventoryMovementType
    Initially one of "Used", "Received", "Repaired"