* mln/convert/from_to.hxx,
	* mln/value/label.hh: add conversion from int_u<n> to label<m>.

	* mln/fun/x2x/rotation.hh,
	* mln/fun/x2x/translation.hh: update doc.

	* mln/labeling/relabel.hh: add a new overload.

	* mln/labeling/wrap.hh: add a new overload with a default argument.

	* mln/util/couple.hh: make it a class.

git-svn-id: https://svn.lrde.epita.fr/svn/oln/trunk@3626 4aad255d-cdde-0310-9447-f3009e2ae8c0