Code blocks are intended to be run as scripts #130
Description
Related to #128.
At the moment, the code blocks in the lesson are often intended to be combined together in a script and run from the command line. We should decide whether we want to continue with this approach or switch to something else, e.g. running code blocks in an interactive environment such as a Jupyter Notebook. This kind of environment is commonly used in other workshops when teaching Python.
If we stick with the scripting approach, the lesson content should be updated to make this more explicit. That will help to avoid issues like #128 where people try to run code intended for a command line script in another environment.
The decision is probably quite strongly related to the question of which image viewer to use, e.g. if we decide to display images inline in the Jupyter Notebook then the code examples will need to be rewritten to fit this choice too.