Added - Classes, instances and solvers for metainferential tableaux
Fixed - Various bug fixes in tableaux systems
1.6.6
Fixed - Natural deduction derivations cannot end with open supopsitions.
1.6.5
Changed - If the different versions of an ND system's rule return the same error in its application, return that error instead of a generic error message.
Fixed - Use ``license_files`` instead of ``license_file`` (deprecated) in ``setup.cfg``
1.6.4
Fixed - Natural deduction system's ``check_derivation`` method now detects if you close a supposition that is not the last open one.
1.6.3
Added - Added versions of the natural deduction systems with reversible ``on_steps``.
1.6.2
Changed - Removed the ``category`` attribute from ``CorrectionError`` (is now inferrable from the numeric error code)