John Butler Trio at Central Park Summerstage (06/15/10) Photo: Jon Klemm Last week, Australia’s John Butler Trio played their biggest New York show to date, a sold out benefit before an enthusiastic crowd at Central Park Summerstage. The next Summerstage event at the Rumsey Playfield is a free show featuring Tinariwen, Omar Souleyman, Toubab Krewe…