* doc/tutorial/figures/tuto4_genericity_and_algorithms-5.ppm,
	* doc/tutorial/figures/tuto4_genericity_and_algorithms-6.ppm,
	* doc/tutorial/figures/tuto4_genericity_and_algorithms-9.ppm: update
	reference file.

	* doc/tutorial/samples/tuto4_genericity_and_algorithms.cc: fix
	threshold function.

	* doc/tutorial/tutorial.tex: include the proper image in step 4.

git-svn-id: https://svn.lrde.epita.fr/svn/oln/trunk@3421 4aad255d-cdde-0310-9447-f3009e2ae8c0