Merrill Garbus is a tour-de-force solo live performer — as we’ve seen with more modestly backed clips of “Doorstep” and “You Yes You” — though it’s time her collaborative efforts get their due as well. Enter w h o k i l l cut “Gangsta,” performed recently on Seattle’s KEXP with bassist Nate Brenner and a pair of dueling saxophones, all of whom were part of the LP’s studio lineup.