[vtkusers] VTK Technical documents directory

[Will Schroeder]

In the vtk.org web pages I've added a "VTK Technical Documents" to the 
side-bar links which points to (http://www.vtk.org/documents.php). Right 
now there is a description of the VTK file formats, a new document about 
parametric surfaces, a technical paper about the ordered triangulator, and 
a paper on parallel processing in VTK in the documents directory. More will 
be added in the future.

Will