Copy the demo notebook to the example dir.

Also
* remove my name, the date, and references to APUG
* rename the notebook "features` to make it more generic
* change a call to `.get_localarrays()` to `.localarrays()`
* remove the "(coming soon)" note about slicing
Use print_function for py3 compatibility.
Reset the prompt numbers.
Merge pull request #463 from enthought/feature/update-demo-notebook

Update demo notebook