“Repect the elders. Embrace the new. Encourage the impractical and improbable, without bias.” These words, originally penned by music journalist David Fricke, were the guiding principles by which Vin Scelsa steered his long-running radio show “Idiot’s Delight”, which ends with Scelsa’s retirement on May 2nd. Scelsa’s close to 50-year career was the embodiment of “old…