The nodes like `<label_type>' are renamed to `<labelType>', so as to
	fit with all other XML files format.

	* data/vaucanson.xsd: Remove underscores in all the compound names,
	capitalize the first letter of the following words. Change weight type
	from decimal to string. Change the minimal number of children of the
	nodes `sum' and `product' from 0 to 2.
	* include/vaucanson/algebra/implementation/series/rat/xml_exp_visitor.hxx,
	* include/vaucanson/xml/xml_chooser.hh,
	* include/vaucanson/xml/node.hh,
	* include/vaucanson/xml/xml_chooser.hxx,
	* include/vaucanson/xml/node.hxx,
	* src/tests/xml/label_node_ref.xml,
	* src/tests/xml/trans_ref.xml,
	* src/tests/xml/geometry_ref.xml,
	* src/tests/xml/r_ref.xml,
	* src/tests/xml/z_ref.xml,
	* src/tests/xml/z_min_plus_ref.xml,
	* src/tests/xml/b_ref.xml,
	* src/tests/xml/z_max_plus_ref.xml,
	* src/tests/xml/fmp_ref.xml,
	* src/tests/xml/session_ref.xml,
	* src/demos/automaton_library/a1.xml,
	* src/demos/automaton_library/b1.xml,
	* src/demos/automaton_library/c1.xml,
	* src/demos/transducers/t1.xml,
	* src/demos/transducers/u1.xml,
	* taf-kit/tests/non_ambiguous.xml,
	* taf-kit/tests/non_ambiguous2.xml,
	* taf-kit/tests/ambiguous.xml,
	* doc/xml/xml_proposal.tex,
	* doc/manual/examples/a1.xml,
	* doc/manual/examples/b1.xml,
	* doc/manual/examples/add1_rt.xml,
	* doc/manual/examples/quot_3_rt.xml: Update accordingly.