Leval Lyde, a 36-year-old Brooklyn rapper who went by the street name "Kevlar," was gunned down yesterday on the corner of Clinton Ave. and Fulton St. in the Fort Greene section of Brooklyn. Lyde was shot just before 5 p.m. on the street corner and declared dead on arrival at Brooklyn Hospital. Lyde had just exited Fish & Crustaceans Quality Seafood and was walking with his sandwich towards the maroon Jaguar (owned by the mother......