First Boston had the Big Dig; now the local NPR station, WBUR, is undergoing its own massive construction project. WBUR’s Executive Editor for Digital Tiffany Campbell, fresh off a collaboration with It’s All Journalism at the Online News Association conference, said that “the redesign,” as it’s known internally, is at the “end of the beginning” of what will be a lengthy overhaul of WBUR’s digital presence.