Something old, something new, something borrowed, nothing blue. That’s the musical motto of ‘The Mightiest Little Band In The Land,’ as they go about dispensing their happy sounds across the country. In this, the third volume by The Lenny Herman Quintet, their warm, lighthearted style sparkles in an album of smooth arrangements for dancing and listening. Here then, as Lenny Herman would put it, is “music people can understand.” The old favorite, Ciribiribin by Alberto Pestalozza, an Italian composer of popular songs and operettas, leads off in an upbeat fashion as each of the intrumentalists gets a chance to display his ability. You’re The One brings on the Hermanaires, the vocal trio within the group, with some heart-to-heart harmony in a modern idiom. A sample of Antonin Dvorak’s great lyric power is offered next in Songs My Mother Taught Me, in which the lilting beat is highlighted by organ and accordion in a big instrumental blend. Then, a happy-as-a-lark breeze with some waltz shading is an instant relie