Add newline at end of file

Silences a compiler warning.

Rendering/Core/Testing/Cxx/TestColorTransferFunction.cxx

@@ -47,4 +47,4 @@ int TestColorTransferFunction(int vtkNotUsed(argc), char* vtkNotUsed(argv)[])
     }
 
   return EXIT_SUCCESS;
-}
\ No newline at end of file
+}