Undocumented predicates

The following predicates are exported, but not or incorrectly documented.

 declare_concept(Arg1)

 declare_concept(Arg1, Arg2)

 add_to_concept(Arg1, Arg2)

 declare_relation(Arg1, Arg2, Arg3)

 add_to_relation(Arg1, Arg2, Arg3)

 concept_select(Arg1, Arg2, Arg3)

 forall_select(Arg1, Arg2, Arg3, Arg4)

 atleast_select(Arg1, Arg2, Arg3, Arg4, Arg5)

 atmost_select(Arg1, Arg2, Arg3, Arg4, Arg5)

 self_select(Arg1, Arg2, Arg3)

 relation_path(Arg1, Arg2, Arg3)

 relation_path(Arg1)

 concept_name(Arg1)

 concept_name_or_not(Arg1)

 num(Arg1)

 concept(Arg1, Arg2, Arg3)

 legitimate_literal(Arg1)

 thread_itemfunctor(Arg1)