improve openfoam reader so that it reads 64bit floats
vtkOpenFOAMReader uses vtkFloatArray to store field values which can store 32 bit floating numbers. It is common to use 64bit floating numbers during OpenFOAM simulations. Adding an option to store 64 bit floats would increase usability of VTK beyond visualization.
https://github.com/Kitware/VTK/blob/master/IO/Geometry/vtkOpenFOAMReader.cxx