A Brooklyn elementary schoolteacher was removed from class and arrested on assault charges yesterday after a 10-year-old student with Down syndrome complained she doused him with air freshener when he passed gas. Jane Fasone, 58, a veteran teacher at Public School 72 in East New York, is accused of spraying the boy's buttocks and mouth and making him stand against a wall, sources said. "It's hard to believe she would do something like that," said Phyllis Esposito, 55, Fasone's neighbor in Marine Park. Esposito said Fasone, the married mother of two adult sons, has taught disabled children for years. "She's...