With its latest release, Omnivore Recordings might as well as be singing “Let It Snow! Let It Snow! Let It Snow!” The intrepid label has unearthed a true rarity for a new digital EP: four previously unreleased songs produced in 1969 by Murry Wilson for an all-but-unknown harmony-pop outfit named Snow. Freshly unearthed from The Beach Boys’ vault, Murry Wilson & Snow: The Break Away EP features Snow’s lush and fully-produced and orchestrated renditions of two songs from Brian Wilson’s songbook (“Break Away” and “We’re Together Again”) and two presumably original tracks…