Screenshots and video

Hi,

there is now one directory per example.
It will be nice to add (at least) one screenshot per example
and also one video per example.

We are using reStructuredText (.rst) for README

Youtube video can be add this way

```
.. image:: http://img.youtube.com/vi/ABCDEFGHIJKL/0.jpg
   :target: https://www.youtube.com/watch?v=ABCDEFGHIJKL
```

where ABCDEFGHIJKL is Youtube Video id

Best regards
