problem: i want to load other types than Python code from external files

solution: extend the %load magic processing to take a filename and afterwards the type that should correspond with a recognized highlighting string - e.g.

%load tox.ini ini would generate the markdown

```ini
[tox]
skipsdist = True

[testenv]
[...]
```

problem: I want to keep my data in contents. lr

solution: if the plugin finds a section wrapped in special comments, the markdown will be inserted in that section e.g.:

<!--JUPYTER_PREPROCESS-->
content from a jupyter notebook

...

lots of it
<!--JUPYTER_PREPROCESS-->

For better styling / interactivity.

defaults for how to handle cells by default

make configurable in configs/jupyter-preprocess.ini, metadata and directly in cell:

• what exactly the fenced code blocks should look like
• global settings for execution behaviour
• full or abridged traceback (global and cell-level)

When a cell is preprocessed and contains no cell-level metadata, the corresponding default value will be used.