Stabilize the sort order of nodes.
Stabilize the sort order of nodes.

Note that this doesn't actually use sortIndex; since we don't have any actual
data in sortIndex yet, it's not a useful sort. sortIndex is redundant and can
probably be removed.

CodethinkLabs/software-dependency-visualizer,CodethinkLabs/software-dependency-visualizer,CodethinkLabs/software-dependency-visualizer,CodethinkLabs/software-dependency-visualizer