(1) Whether the presence of a subsidiary state property law issue in a 11 U.S.C. § 541 action brought against a debtor to determine whether property in the debtor’s possession is property of the bankruptcy estate means that such action does not “stem[] from the bankruptcy itself” and therefore, that a bankruptcy court does not have the constitutional authority to enter a final order deciding that action; and (2) whether Article III permits the exercise of the judicial power of the United States by the bankruptcy courts on the basis of litigant consent, and if so, whether implied consent based on a litigant’s conduct is sufficient to satisfy Article III.