standard cmake

mkdir build; cd build; ccmake ..
- For RHEL7, opengl2.1 might not be able to run regular VTK library
- Use 7.1.1
  - Set VTK_RENDERING_BACKEND=OpenGL while the default is OpenGL2
- wrap with python or conda when available
- Choose python version as 2 or 3
make -j 10; make install
Copy $PREFIX/lib/python3.x/site-packages/vtk to $PYTHONE_HOME/lib/python3.x/site-packages