Update to GDP and Federal Funds Rate Data

CMD strives for innovation - large and small. Today two small changes have been made. 

Nominal GDP has been changed from being updated with the Atlanta Fed's GDP NOW to the NY Fed's GDP tracker.  This is solely due to the structure of updates to the NY Feds GDP tracker. In addition, the nominal component of GDP is now being updated with mean GDP deflator forecasts from the Philadelphia Fed's Survey of Professional Forecasters.  This change to the GDP series will be reflected in all of the series which rely on nominal GDP as a normalizer.      

CMD has also added the federal funds rate to the database. The series will start in April of 1928, and its history comes from Sriya Anbil, Mark A. Carlson, Christopher Hanes, and David Wheelocks' new working paper, "A New Daily Federal Funds Rate Series and History of the Federal Funds Market, 1928-1954."