Support JSON Seriliazation for unsaved WorkOrder

[ShawnTalbert]

It was reported that if you try to log a newly instantiated WorkOrder you get an error,

Set the workorder assemblyitem then log the workorder, NS barfs with:

 You cannot create an inventory detail for this item

Perhaps adding explicit skip logic for the workorder.item.inventorydetail subrecord in toJSON()? Is this useful for all sublists?

[ShawnTalbert]

We do a similar workaround for xxxText fields to allow unsaved records to be logged (it skips logging of *Text fields in toJSON())