Added one-way option to segment (used to add (or not) connections and steps for both directions). Stopped adding previous line station to line stations (line stations can't know that). Fixed outdated synopsis example.
Remove use Type::Utils -> maybe reduces warnings
Added is_one_way attribute.
Removed unused (and faulty) is_transfer_to_next() and is_transfer_from_previous() methods from LineStation. This is handled by Step.
Rewrote ::Cmd::Lines, since it was built upon now-removed methods in LineStation.