Wrong falling check. We don't need to check for repose
because that's already handled by an ABM. Instead use the
standard check_for_falling that's recursive.
Use interception where possible to modify destintion for items
directly instead of relying on post-hoc inventory rearrangement.
This should resolve the glitches where items appear in the wrong
place in inventory for a flash before being moved.
- Nodes that are falling do damage to those near to them from
crushing and/or friction.
- Player activity can cause falling nodes left in precarious
positions by mapgen to fall randomly.
