At yesterday's Miami City Commission meeting, a small group of neighborhood preservationists came prepared to do in Eric Silverman, owner of the Vagabond Motel on Biscayne Boulevard in the Upper Eastside. Members of the MiMo Biscayne Association and residents railed against Silverman's use of his property for an open-air farmer's market on the weekends. They pleaded with city commissioners to deny his request to make the venture a permanant fixture. To their credit, city commissioners did not le