Wrap VTK properties to pythonic properties with snake_case names

Add properties for python wrappers

The properties of a VTK object can now be accessed in a pythonic style.

Example:

i = vtk.vtkImageData()
print(i.dimensions) # prints (0, 0, 0)
i.dimensions = [2, 2, 3]
print(i.dimensions) # prints (2, 2, 3)
print(i.reference_count) # prints 1

Accept keyword arguments in constructor for python wrapped VTK classes

In python, you can now initialize the properties of a wrapped VTK class through specifying keyword arguments in the constructor.

Example:

s = vtkSphereSource(center=(1, 0, 0), generate_normals=False, radius=10, theta_resolution=20)
e = vtkElevationFilter(low_point=(1, 0, -10), high_point=(1, 0, 10), input_connection=s.output_port)
e.Update()
print(e.output.point_data.scalars.range) # prints (0.0, 1.0)

Conveniently build and reuse pipelines with vtkAlgorithm and vtkDataObject

Example:

pipeline = (
vtkElevationFilter()
  >> vtkShrinkFilter()
  >> vtkGeometryFilter()
  >> vtkPolyDataConnectivityFilter(color_regions=True, extraction_mode=VTK_EXTRACT_ALL_REGIONS)
  >> vtkPolyDataNormals()
)
cone = vtkConeSource(radius=5, resolution=8, height=2).execute()
print(pipeline.execute(cone))
cylinder = vtkCylinderSource(radius=6, resolution=9, height=3).execute()
print(pipeline.execute(cylinder))