* mln/accu/bbox.hh,
	* mln/accu/count.hh,
	* mln/accu/histo.hh,
	* mln/accu/max.hh,
	* mln/accu/max_h.hh,
	* mln/accu/mean.hh,
	* mln/accu/min.hh,
	* mln/accu/min_h.hh,
	* mln/accu/nil.hh,
	* mln/accu/p.hh,
	* mln/accu/pair.hh,
	* mln/accu/sum.hh,
	* mln/accu/v.hh: Update inheritances (from Accumulator to base_).

git-svn-id: https://svn.lrde.epita.fr/svn/oln/trunk@1237 4aad255d-cdde-0310-9447-f3009e2ae8c0