Optimize Traversal#each_node allocations
Optimize Traversal#each_node allocations

This removes the need for allocating an Array for every set of child
nodes.

dfockler/oga,altmetric/oga,altmetric/oga,jeffreybaird/oga,ttasanen/oga,ttasanen/oga,ttasanen/oga,jeffreybaird/oga,altmetric/oga,dfockler/oga,YorickPeterse/oga,dfockler/oga,YorickPeterse/oga,YorickPeterse/oga,jeffreybaird/oga,dfockler/oga,YorickPeterse/oga,YorickPeterse/oga,jeffreybaird/oga,altmetric/oga,ttasanen/oga,ttasanen/oga,jeffreybaird/oga,dfockler/oga,altmetric/oga