Removing lib prefix if compiled with vtk7
solved the problems pointed out by the upstream
Added vtkRenderingOpenGL2 as lib dep to vtkgdcm...
Changes to compile vtk apps and vtk examples wi...
Removed vtkCxxRevisionMacro
vtkgdcm examples adapted to vtk6
defining vtkFloatingPointType as double
VTK applications adapted to VTK6