* Bugs fix for the Windows build with VC6

  * Bugs fix for the Windows build with VC6
  * CMakeLists.txt : bug fix - The include of the VTK lib is made only when it's
    needed (only for projects required VTK). If the VTK is included in all
    projects, there is conflicts with the jpeg lib of vtk when compiling the
    gdcmjpeg[8,12,16] projects. The first conflict is on the jmorecfg.h file.
  * src/gdcmUtil.h : export binary_write methods. Otherwise, there's problems
    when compiling the gdcm_wrap.cxx file (created by the compilation of the
    gdcm.i file)
  * vtk/vtkGdcmDemo.cxx : remove the use of std namespace for the cerr use
    (like it's already made for the cout use). Otherwise, conflict with the
    std::cerr of vtk.
   -- BeNours