By LUIS BENAVIDES and MANUEL RUEDA, Associated Press MEDELLIN, Colombia (AP) — Eight-year-old Eros trots through the streets of this hilly city several times a day with a straw basket in his jaws, taking vegetables, fruit and packaged foods to customers of the El Porvenir mini-market. The chocolate Labrador retriever is paid with treats and massages of his furry head.