(Image credit: Sony Pictures Classics) In case you missed it, the one and only Meryl Streep has been having quite the spring. The acting icon just had the biggest box-office opening of her legendary career with " The Devil Wears Prada 2 "; since hitting theaters on May 1, it has pulled in a whopping $433 million globally and left us wondering with bated breath about when it might come to streaming . It's a nostalgia-inducing reprisal of one of her best roles ever , as Runway editor-in-chief Miranda Priestly, but with such an acclaimed and stacked filmography as Streep's, there's bound to be loads of lesser-known but equally great performances to discover in the performer's catalogue. And Meryl's work in the Irish period drama "Dancing at Lughnasa" is just that, featuring one of my favorite performances from the Oscar-winning star. What is 'Dancing at Lughnasa' about?…