* include/vaucanson/automata/implementation/iterators/transition_iterator_base.hxx:
Fix constness in next().
* include/vaucanson/automata/implementation/iterators/delta_transition_iterator.hh,
* include/vaucanson/automata/implementation/iterators/delta_transition_iterator.hxx:
Add typedef to simplify type names.
Add default return value in op_weight().