Increase consistency across episodes

[jhlegarreta]

Episodes should be made consistent:

• Some Jupyter notebooks still contain the output cells (e.g introduction or DTI. This might be interesting for the solutions, to have a reference of what the output should look like (although they should be in the markdown files as well) but I'd say that it is not for the raw notebooks that will be used for teaching.
• We should maybe decide if Jupyter notebooks will contain the static images. I would maybe remove them. This saves maintenance work (until an automatic method that works flawlessly is found Automatically generate the Markdown episodes from the Jupyter Notebooks? #85) and reduces the risk of discrepancies between the episode markdown and notebooks.
• Similarly, some episodes (e.g. DTI) do not contain the instructions to save the figures, whereas others do (e.g. CSD, tracking). Although this is strictly not relevant for learners, it is useful for developers; otherwise, they need to manually add the commands every time a change to the figures is needed.
• We should define as variables initialized at a single place and value values that are used repeatedly (e.g. the subject id, the FA threshold, etc.). Eases maintenance and reduces the possibility of incurring into bugs.

[kaitj]

Some Jupyter notebooks still contain the output cells (e.g introduction or DTI. This might be interesting for the solutions, to have a reference of what the output should look like (although they should be in the markdown files as well) but I'd say that it is not for the raw notebooks that will be used for teaching.

I think the intro notebook is just a matter of not having been updated yet. The DTI I may have missed. Will clear this one when I add the exercises for #30 or #105.

We should maybe decide if Jupyter notebooks will contain the static images. I would maybe remove them. This saves maintenance work (until an automatic method that works flawlessly is found #85) and reduces the risk of discrepancies between the episode markdown and notebooks.

This might have just been a result of trying to match notebooks with markdown files. Definitely a discussion to be had, but I am ok with removing figures that are generated out of the notebook.