* mln/core/p_set.hh (mln::p_set<P>::point): New typedef.
	Use it...
	(mln::p_set<P>::bbox): ...in the declaration of this method.
	(mln::p_set<P>::bb_): Make it mutable.
	Change type from `accu::bbox<P>' to `accu::bbox<point>'.
	(mln::p_set<P>::bb_needs_update_): New attribute.
	(mln::p_set<P>::update_bb_): New method.
	(p_set<P>::p_set): Adjust ctor.
	(mln::p_set<P>::insert)
	(mln::p_set<P>::remove)
	(mln::p_set<P>::clear)
	(mln::p_set<P>::bbox):
	Adjust methods.
	* tests/core/point_set_compatibility.cc: Exercise
	p_set< graph_psite<point2d> >.


git-svn-id: https://svn.lrde.epita.fr/svn/oln/trunk@2078 4aad255d-cdde-0310-9447-f3009e2ae8c0