Kitware/tangelo — pull request #308 by aslagle (2014-04-11 18:20:08+00:00)
Title: Dendrogram's d3 version compatibility

In older versions of d3 (specifically 3.1.4 which is still used by meteor's core d3 package), a bunch of the x's get set to NaN because node.children is an empty array rather than undefined.

I think this also just makes it generally more robust.