Remove basic_demo.py.

features.ipynb eclipses it I think.
Remove old julia-set example.
Remove some extraneous examples.

I think features.ipynb eclipses all of these.
Move distarray protocol stuff into its own folder.
Rename example folders to use underscores

...instead of dashes.  So they can potentially be used as subpackages.
Merge pull request #560 from enthought/feature/rearrange-examples

Rearrange examples