By now, it should have been a bustling hotel surrounded by shops and condos in downtown Boston. But a gaping hole is all you’ll find at the site of the original Filene’s Basement. Meanwhile, in Allston, Harvard University’s ambitious plans for a science center are on hold indefinitely. And there’s nothing but green on the Rose Kennedy Greenway – no construction in sight. As the credit crunch drives Boston’s development into a brick wall, can developers and the city find a way forward?