REUTERS/Steve Marcus (Reuters) - Activist investor Daniel Loeb's Third Point LLC hedge fund on Sunday unveiled a more than one percent stake in Nestle SA and said the world's largest packaged foods maker needed to improve margins, buy back stock and shed non-core businesses. Third Point, which disclosed its Nestle position in a letter to investors, also said the food company should sell its 23 percent stake in French cosmetics firm L'Oreal.