SCIENCE-FICTION fans everywhere have heard of the futuristic law enforcer Robo Cop. Now, inventive youngsters, including 12-year-old Ashley Fowler, of Middlesbrough, have got their teeth into an invention of their own, with just as much bite - Robocrocs.The mechanical miniature snappers are being produced at the University of Teesside, Middlesbrough, the products of a technology summer school for dozens of youngsters, aged between ten and 14 from all 12 secondary schools in Middlesbrough, and some primary schools