mbostock/d3 — pull request #1580 by jasondavies (2013-10-11 10:44:19+00:00)
Title: Remove the children array for childless nodes.

If data is updated so that some nodes no longer have children, and a
custom children accessor is used, then the children array was not being
removed for such nodes, which meant that hierarchical layouts were
incorrectly taking into account these children.

Fixes #1579.