Deal with inventory slots with item restrictions

[fechan]

Right now the transfer calculator assumes empty slots will accept any item, which is untrue for things like Brewing Stands and who knows what else. The calculator might create a transfer order for an item into an incompatible slot, which prevents other possible items from transferring since it thinks the slot has been filled.

[fechan]

We can't detect if items cannot transfer without first trying to transfer them, so it's probably best to notify the user there is a pipe with failing transfers and advise them to add a filter or check if the destination is a read-only slot.