Automatically called for facet merging and Voronoi diagrams

<<QhullVertex does not print facetNeighbors() if !facetNeighborsDefined()
      Was not caught by QhullVertex_test due to facet merging

Fixed type of vertex->neighbors in qh_printvoronoi [no effect on results]

Removed unnecessary if statement in qh_printvoronoi

index.htm: Add Google Scholar references