Long before Catholic nuns emerged from their habits following the liberalizing edicts of Vatican II, Sister Anna Mary Kelly, wearing the black, full-length garb modeled on the 17th-century dress of the Sisters of St. Joseph, had some forward-looking ideas of her own. Sister Kelly, a former dean and professor at Regis College in Weston and its campus in Framingham and a former president of her order who spent her life working on behalf of its ministries, died April 18 of congestive heart failure at Bethany Health Care Center in Framingham.