[vtkusers] 2 library paths in CmakeLists.txt for MVisual C++ v6

[vanessa.noguesruiz at epfl.ch]

Hi everybody!

Does anybody know how to include 2 libraries in a cmakelists.txt file, I mean, 
I have already set the path for VTK library because it's already done, but when 
I want to include the path where I've put GSL library - because I work on 
Windows and I have to include it for my project- it gives me the error that 
it's not able to find a gsl_*.h file. I am trying to modify Cmakelists.txt 
adding a new directory where going to look for the added .h, but it doesn't 
work.
Thanks in advance.
Van