New port: math/vtk8: Visualization toolkit (repocopy of math/vtk6 with modifications)
Changes against math/vtk6:
- Use DISTVERSION
- Update COMMENT
- Add to USES
- Remove the SHARED option: all libraries should be shared, no need for the option to do otherwise
- Remove the PYTHON option: python binding should be a separate port
- Modernize the port: use helpers instead of .if/.endif
- Use autoplist: too many files with too complex dependencies on options
- Update USE_QT to include missing parts