* Iterator-based access to edges
* vtkGraph subclasses from vtkDataObject instead of vtkPointSet
* vtkGraph's implementation is much more like that of the boost graph library
* Separate classes vtkDirectedGraph and vtkUndirectedGraph instead of
a Directed flag
* Mutable classes vtkMutableDirectedGraph and vtkMutableUndirectedGraph used for building graphs

ENH:Added the ability to have number of bins in any dimension to be equal to one or more; added logic and controlling data memebers to prevent the insertion of duplicate triangles

ENH: Add a new option to tell the filter to only create one vertex per cell instead of a polyvertex with many vertices in one cell.

BUG: When append poly data canot allocate enough memory. Try to exit cleanly instead of bringing the whole app down.

BUG: ClipDataSet was not passing the array to process information to ClipVolume. Also, ClipVolume worked only with scalars

ENH: Correct the memory leaks and parallel bugs in vtkDataObjectGenerator and enable it in VTK and ParaView.

ENH: Add source that demonstrates how to generate most of the vtkDataObjects, including the composite ones.