We’ve seen them tear the roof off Stubb’s, a record store, and wherever their EP might be played, but here’s a more subdued side to Alabama Shakes: Presumably set to appear on this spring’s debut full-length, “Boys and Girls” finds Brittany Howard and Co. in familiar soulful territory, yet this time for some tender reflection on the breakup of a childhood friendship. Check out their moving live take at Virginia’s WNRN above, replete with light acoustic backing, an iPad app keyboard, and a bittersweet whistle solo.