An American college student from Montgomery County, arrested a week ago during protests in Cairo, is back on U.S. Soil. He arrived at Philadelphia International Airport on Saturday night.  19-year-old Gregory Porter of Glenside met his mother, Nancy Hansen and his father, Adrian Porter, and they got into a waiting Land Rover and drove home.  He and two other students were arrested on the roof of an American University at Cairo building, where they were accused of throwing firebombs at security forces on the ground.  He’s a Drexel University student who was studying in Egypt.  The other two are also back in the U.S.A.