FEATURE: Added Product Inventory Creation and Mass Deletion to API

Added (beta) the ability for Web Service call Product_UpdateInventoryViaDataSet to create objects not found with basic required information

Does not support creating VariantInventory products, only regular products.; 

Required columns are:

CreateIfNotFound (if this column is on the dataset all products are added if not found) Manufacturer (will create if not found)

Added (beta) new web service call for mass, high-speed deletes

Currently only works with ItemNr as the LookupKey as noted on web service description:

Product_DeleteProductsViaLookup(string[] psItemLookups, string psLookupKey)