add exception for linking with Paraview (from Kitware, Inc.)

LICENSE.txt

@@ -3,13 +3,13 @@ Gmsh is provided under the terms of the GNU General Public License
 
   The copyright holders of Gmsh give you permission to combine Gmsh
   with code included in the standard release of TetGen (from Hang 
-  Si), Netgen (from Joachim Sch"oberl), METIS (from
-  George Karypis at the University of Minnesota) and OpenCASCADE
-  (from Open CASCADE S.A.S) under their respective licenses. You may
-  copy and distribute such a system following the terms of the GNU 
-  GPL for Gmsh and the licenses of the other code concerned, provided
-  that you include the source code of that other code when and as the
-  GNU GPL requires distribution of source code.
+  Si), Netgen (from Joachim Sch"oberl), METIS (from George Karypis
+  at the University of Minnesota), OpenCASCADE (from Open CASCADE
+  S.A.S) and ParaView (from Kitware, Inc.) under their respective
+  licenses. You may copy and distribute such a system following the
+  terms of the GNU GPL for Gmsh and the licenses of the other code
+  concerned, provided that you include the source code of that other
+  code when and as the GNU GPL requires distribution of source code.
 
   Note that people who make modified versions of Gmsh are not
   obligated to grant this special exception for their modified