* doc/tutorial/doxyfile_tuto.local: new doxyfile. Generate only the
	tutorial.

	* doc/tutorial/figures/extend-1.ppm,
	* doc/tutorial/figures/extend-2.ppm,
	* doc/tutorial/figures/extend-3.ppm,
	* doc/tutorial/figures/extend-4.ppm,
	* doc/tutorial/figures/extend-5.ppm,
	* doc/tutorial/outputs/extend.txt: new reference files for the new
	example.

	* doc/tutorial/samples/Makefile.am,
	* doc/tutorial/samples/extend.cc: new example for the tutorial,
	related to the image extension.

	* doc/tutorial/samples/ima2d-rot.cc: use extended_to().

	* doc/tutorial/tools/todoxygen.sh: support keyword subsubsection.

	* doc/tutorial/tutorial.tex: add more details about image extension.

git-svn-id: https://svn.lrde.epita.fr/svn/oln/trunk@3419 4aad255d-cdde-0310-9447-f3009e2ae8c0