• Fix Notebook to demo DP histograms with cut #46
• Fix Explain utf8-lossy in templated code #42
• Fix Think about notebook execution #36

Dropped the expected-script test: when it was short, it was useful, but now it just means that every change requires a corresponding update to the test: Better to have finer grained unit tests that catch problems earlier.

In the notebook template, added lots of comment blocks that will be turned into markdown cells. The # + and # - are the jupytext light format.

This is a change, but I think that having the executed notebook be the real release from the perspective of this application makes sense: That's the best way of making sure the code in the notebook does what we think it should do.

For reviewer:

• This would be a good one to checkout and run end to end. (With the name change, you'll need to run flit install before you can execute dp-wizard.)
• There is a lot undone, so don't worry about gaps, but if something is just wrong, that would be good to hear about.
• After this, I want to take some time to clean up the internals, but there won't be big changes in the UI... so if something would be really good to get sorted before the demo next week, that would be good to note.