geom/m44752: false occupancy aware neighbour determination
The neighbour pattern for a node indicates occupied neighbouring nodes. This commit updates the definition of occupancy for the (x-1), (y-1), and (z-1) neighbours to be occupied if the neighbour's adjoining children (ie sharing a face with the current node) are occupied. In the 1-D figure below, at a depth d, the node 'X' has two occupied neighbours 'R' and 'L'. When determining the neighbour pattern of X, the (x-1) state of the neighbour's adjoining child ('r') is used instead. For completeness, nodes marked with '?' are not causally available. d+0: R|X|L d+1: Rr|??|??