ccx2paraview v3.0.0

Full refactoring of .vtk/.vtu/.pvd writers - now they use native Python VTK library. Legacy .vtk format is fully supported - previously there was a problem with component names.

Convert .frd into both formats at once:
ccx2paraview.Converter(file_name, ['vtk', 'vtu']).run()

Von Mises and principal components are written as separate scalar fields. Tensor fields are exported as tensors with 6 components. It makes possible to apply TensorGlyph filter in Paraview.

Thanks to Nuitka - a new binary generation tool - ccx2paraview binaries are lightweight in comparison with the one generated by PyInstaller.

Perfect test results!