* mln/arith/min.hh,
	* mln/clustering/kmean_rgb.hh,
	* mln/world/rgb/invert.spe.hh: Remove duplicate references to
	mln_trace.

	* tests/data/fill_with_image.cc,
	* tests/data/paste.cc,
	* tests/linear/gaussian.cc,
	* tests/opt/at.cc,
	* tests/opt/element.cc,
	* tests/opt/value.cc: Remove useless include.

	* tests/unit_test/unit-tests.mk: Remove mln_trace_* tests.