After dropping two solid singles, "Supa Star" and the title track "Livin' Proof," during the past year, the rappers Lil' Dap and Melachi the Nut Cracker come through like glue on the long play. On Livin' Proof, they stick to the same formula of sparse, monotonic rhymes over Gang Starr producer DJ Premier's intricately crafted and hook-laden moodscapes. Though neither Dap nor Mel is likely to be...