Stocks rallied around the world on Thursday, pushing the broader market in the United States back onto positive ground for the year, after European leaders reached a deal to spread the pain of restructuring Greece’s debt and try to bring the crisis in the euro zone under control. While the deal helped to restore confidence to the financial markets, analysts noted that questions remained about how it would be implemented. They also worried that fully fixing the problems of excessive debt and weak growth could take years. Officials also agreed that European banks would need to raise more capital and said they would increase the euro zone bailout fund to $1.4 trillion, a move that they hope will provide the capacity necessary to keep Italy and Spain from following Greece’s painful path. Will Euro Zone troubles be fixed by bailouts?