* mln/topo/is_simple_2d.hh (mln::connectivity_number_2d): Create
	the configuration number by considering that the first (resp.
	last) neighbors (in the forward browsing order) represent the
	least (resp. most) significant bits of the configuration number,
	as does the algorithm that computed the 8-c and 4-c LUTs (arrays
	mln::connectivity_number_c8 and mln::connectivity_number_c4).
	* mln/topo/connectivity_number_2d.hh: New.
	* mln/topo/is_simple_point2d.hh: Fix dates in copyright header.
	* tests/topo/connectivity_numbers_2d.cc: New.
	* tests/topo/Makefile.am (check_PROGRAMS):
	Add connectivity_numbers_2d.
	(connectivity_numbers_2d_SOURCES): New.