* mln/io/dump/load.hh,
	* mln/io/dump/save.hh:
	  - Add new information in the header.
	  - Add more assertion on value type, dimension and file type.

	  Important note: Old dump files are not compatible with this new
	  format.

	* mln/trait/value_.hh: add a new macro mln_trait_value_name.

	* mln/value/builtin/floatings.hh
	* mln/value/builtin/integers.hh
	* mln/value/builtin/symbolics.hh
	* mln/value/int_s.hh
	* mln/value/int_u.hh
	* mln/value/label.hh
	* mln/value/rgb.hh: add name() member to value_<> specialization.
	  It returns the type name as a const char*.

	* tests/io/dump/dump.cc: add new tests with builtin types.

git-svn-id: https://svn.lrde.epita.fr/svn/oln/trunk@3508 4aad255d-cdde-0310-9447-f3009e2ae8c0