Refactorings

[finsberg]

• Restructure the files a bit so that it is clear which commands belongs to which file types.
• Add a lot more unit tests
• Add documentation for script for converting between different formats
• Add command line interface for converting between different formats

[cdaversin]

Looks great !! The file re-organisation makes it much clearer, with the corresponding command line (and consistent naming). And good job with all the unit tests and documentation 👏