With Record Store Day just a little over three weeks away, Omnivore Recordings has unveiled an eclectic slate of three vinyl platters suiting the label’s deliciously omnivorous tastes.  Two artists are familiar to fans of the label, while the third makes an Omnivore debut.  All of the titles, of course, will be offered via your local brick-and-mortar independent music retailer on Saturday, April 20 to mark the sixth annual event. Without further ado…hit the jump to dive into tasty treats from Big Star, The Old 97’s with special guest Waylon Jennings, and…