Previously, with two fans facing into each other, either one of them would completely overpower the other, or they'd cancel each other out. Now the force is inversely proportional to the distance, so the items end up in the middle
Added IBlowable for fan; created TE for a piston-based inserter (IInsertable). The former will improve cooling for pile setups and the latter will allow for automation, in combination with comparator output for pile fuel.