SPRINGFIELD - David Wetzel's "veggie mobile" rolls along, past the digital signs at gas stations that fluctuate almost daily, sending fear into the hearts of motorists. "I don't pay any attention to them," says Wetzel, who travels about 45 miles for every gallon of free fryer oil he puts into his 1986 Volkswagen Golf. Wetzel, 79, of Decatur was in a particularly good mood Thursday, after winning another victory in the state legislature. A bill that Wetzel inspired, which will make it easier to legally drive a vegetable oil-powered vehicle, was unanimously approved by a House committee. "It's quite exciting....