Updated the translations.
Updated the unit tests.

Same as Odoo 8 ones.

Note that when the account move date is empty an exception:
constraint null value is raised during execution of action_move_create() method.

Add force_period_on_date context to always make the period be around the current date.

Note that we send a accounting date in reverse_moves func and
the fill_acocunting_date should use it instead of today date.

Remove a "special" field & rename an action.

Updated the translations.
Executed "black" and "isort".

it existed in previous versions

Those fields are similar to old odoo fiscalyear fields
Also added tests

(taken from the related account.move object)