This allows hoppers to dump the items they're ingesting out into the
world if there's not a compatible inventory to receive them (and the
target node is "open", tested via buildable_to)
Consistency is now maintained for side and vertical hoppers regarding
which face of a target node they inject items into. Injecting from the
top goes to the same inventory regardless of what hopper type did the
injecting, and likewise injecting from the side goes ot the same
inventory.
