Main changes:
- ***possible_parameter*** and ***run_jnb*** have a new optional parameter *jsonable_parameter = True* that constrains the possible parameters to the set of jsonable parameters,
- ***possible_parameter*** returns a list of possible parameters with their name, value (if *jsonable_parameter = True*) and cell index. The list is sorted alphabetically by the name of the possible parameters.
A **jsonable parameter** is a parameter for which its value can be recovered from its json representation (using the json module).