While New Yorkers have been immersed in the Bard courtesy of the Royal Shakespeare Company’s visit to the Park Avenue Armory, the highlight of the summer theater season in Washington has been a visiting troupe from Down Under. The Sydney Theater Company production of Chekhov’s “Uncle Vanya,” starring Cate Blanchett as Yelena, plays the Kennedy Center through Aug. 28. Charles Isherwood joins Jeff Spurgeon in the studio to find out more about how the creative team and the big name star jive with the script.