Nearly four years after VNG.co set out to build a nationwide fueling network for compressed natural gas, the Bala Cynwyd company last week launched its first outlet: a single pump at a BP Station next to a Roosevelt Expressway on-ramp. That Gov. Corbett would come to East Falls to inaugurate one fuel pump might indicate that VNG.co L.L.C. has bigger ambitions than building a few natural gas vehicle fueling stations.