Reset score of each matches to follow self order

Usefull when you need to apply one sorter over another.

Property definitions

nitc $ IndexMatches :: rerank
	# Reset score of each matches to follow `self` order
	#
	# Usefull when you need to apply one sorter over another.
	fun rerank: IndexMatches do
		var res = new IndexMatches
		for match in self do
			res.add match
			match.score = res.length
		end
		return res
	end
src/model/model_index.nit:500,2--510,4