Version 4.1.1

[4.1.0] 2022-01-17

Added

• Make specification iterable
• Add a get_comb_class method to combinatorial specification

Changed

• The get_terms now have unique keys for the parameters to save memory.
• CombinatorialSpecification.expand_verified will try to find a spec
  allowing reverse rules if it fails without.
• The labels assigned to nodes will always be in DFS order now.

Fixed

• Fixing bug creating non productive forest when expanding verified classes
• Handled properly when user asks for an random object of a size the class does
  not have
• Trying to verify the class being expanded when expanding a combinatorial
  specification.
• Bug in complement constructors inside equivalence path rules.