[vtkusers] New 3d linear elements

[Mathieu Malaterre]

Hi all,

	Thanks to the hard work of Jean Favre, VTK has now two new 3d linear 
elements:

   - vtkPentagonalPrism
and
   - vtkHexagonalPrism

Also a very big thank goes to Philippe Guerville who developed these 
classes and Charles Pignerol (CEA-DAM, France) who ported this class under
VTK 4.

Please fill free to send comments and suggestions to either Jean or myself.

Thanks
Mathieu