Worst cost of all the link's costs

Property definitions

a_star $ PathContext :: worst_cost
	# Worst cost of all the link's costs
	fun worst_cost: Int is abstract
lib/a_star/a_star.nit:343,2--344,32

a_star $ ConstantPathContext :: worst_cost
	redef fun worst_cost do return 1
lib/a_star/a_star.nit:369,2--33

a_star $ WeightedPathContext :: worst_cost
	redef var worst_cost is noinit
lib/a_star/a_star.nit:395,2--31

a_star $ PositionPathContext :: worst_cost
	redef var worst_cost = 0
lib/a_star/tests/test_a_star.nit:287,2--25