equivalent_classes is now a Set, not a List*.
Bugfix in dynamic_hash_table_init. subsumers and direct subsumers are now Set instead of Set*.
Members of the union class_description are now structs, not struct pointers.
Added hash_map_reset function that frees the space allocated for the elements of a hash map.
Changed told_subsumers from List* to List.
Changed predecessors from Link** to Link*
Changed successors from Link** to Link*
Changed first_conjunct_of and second_conjunct of from HashTable* to Set.
Changed first/second_conjunction_of_list from ClassExpression** to List.
List initialization function is now a macro.
The first/second_conjunct_of are now Set*. It is more efficient in terms of space since not every concept has to have it and more efficient in terms of CPU time since we save the time in parsing used for initializing the fields of the Set.