Made script testable by using absolute URLs, closing https://github.com/google/primarysources/issues/19.
Made script testable by using absolute URLs, closing https://github.com/google/primarysources/issues/19.

dublebuble/primarysources,cesarmarinhorj/primarysources,dublebuble/primarysources,cesarmarinhorj/primarysources,cesarmarinhorj/primarysources,cesarmarinhorj/primarysources,dublebuble/primarysources,dublebuble/primarysources