* mln/neighb/image.hh: New.
	Provide a morpher adding a neighborhood to an image.
	* mln/neighb/get.hh: New.
	Get the neighborhood from an image with neighborhood.
	* mln/metal/has_neighborhood.hh: New.
	Provide a static assertion `has_neighborhood' for images.
	* mln/tag/skeleton.hh (mln::tag::neighb_): New tag.
	* mln/trait/ch_value.hh
	(trait::impl::ch_value_< M< tag::image_<I>, tag::neighb_<N> >, V >):
	New specialization for mln::neighb::image<I, N>.
	* tests/Makefile.am (SUBDIRS): Add neighb.
	* tests/neighb/Makefile.am: New.
	* tests/neighb/image.cc: New.
	Exercize mln/neighb/images.cc and mln/neighb/get.cc.


git-svn-id: https://svn.lrde.epita.fr/svn/oln/trunk@1686 4aad255d-cdde-0310-9447-f3009e2ae8c0