VASP / molecule rendering improvements
This branch is probably larger than it should be, but many of the changes were dependent.
- IO/Legacy support for vtkMolecule (extends vtkGraphReader/Writer) + test.
- Lattice and LatticeOrigin member for unit cell representations in vtkMolecule.
- Unit cell rendering support for vtkMoleculeMapper + test.
- Custom atomic radii support in vtkMoleculeMapper + test.
- Support for changing color array/lookup table for vtkMoleculeMapper.
- vtkCountFaces filter, use to annotate cell data with the number of faces in a cell.
- vtkVASPTessellationReader and vtkVASPAnimationReader for new VASP file formats.