vtkBiQuadraticQuadraticHexahedron docu update and InterpolationDerivs bugfix
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
The attached patch for the vtkBiQuadraticQuadraticHexahedron class updates the documentation and fixes the InterpolationDerivs calculation.
The derives are computed in [-1; 1] but need to be converted in [0; 1] coordiantes.
Additional some typo fixes are made.