Remove all the instances matching on `query`

Property definitions

	# Remove all the instances matching on `query`
	fun remove_all(query: nullable QUERY): Bool is abstract

lib/popcorn/pop_repos.nit:198,2--199,56

	redef fun remove_all(query) do
		return collection.remove_all(query or else new JsonObject)
	end

lib/popcorn/pop_repos.nit:357,2--359,4