A raucous all-night Brooklyn house party ended in bloodshed early Saturday when a reveler was gunned down, with neighbors describing the East New York residence as a weekly nuisance with booming music and heavy boozing. Kelson Fleary, 37 — who was once charged with attempted murder — was leaving the gathering around 5:20 a.m. when he became a victim, fatally shot by a gunman who trailed him ...