Mathmaker

---------------------------

* Add y2b2 mental calculation level.
* Remove some deprecation warnings in tests.

---------------------------

* Update y1b2 mental calculation level.
* Read metadata from pyproject.toml (not all of them yet, though)
* Update french translation.

---------------------------

* Add "belts" directive.
* Update y2b1 mental calculation level.

---------------------------

* divi_vocabulary questions may now be asked using numbers not divisible by each other (answer is a fraction)
* Add y2b1 mental calculation level.

---------------------------

* Patch version (some more required files included).

----------------------------

* Patch the daemon to let it accept the new YAML sheet names.
* The output dir will always be in user's home.
* Fix several bugs.