* include/Makefile.am: Add new files.
* include/vaucanson/automata/implementation/iterators/state_iterator.hh,
* include/vaucanson/automata/implementation/iterators/state_iterator.hxx,
* include/vaucanson/automata/implementation/iterators/state_iterator_base.hh,
* include/vaucanson/automata/implementation/iterators/state_iterator_base.hxx:
New. Interface & implementation.