Add demo videos of actions performed
  - Add demo videos for the following actions: moving data, rotating data, slicing data and zooming in/out of data.
  - Add a demo video 'leapMotion.total.mp4' showing a combination of slicing, rotating and zooming in/out of data.
Merge branch 'master' of https://github.com/VictorLoren/leapmotion-paraview