MCCARTNEY MANIA: No sooner had the multitasking Stella McCartney wrapped up her spring 2012 show than she was on to her next project — her father’s wedding to Nancy Shevell. McCartney dressed the bride, the groom, herself, and the children. Shevell, who became Sir Paul McCartney’s third wife over the weekend in a small ceremony in London, wore a “simple and understated, off-white dress to the knee,” according to a spokesman for the designer. McCartney dressed her father in a bespoke tailored suit, and her children, nieces and nephews in Stella McCartney Kids. The couple married at the Marylebone Register Office on Sunday and held a reception at their north London home for about 30 guests.