Add code to fill in unlabled recession indicators

In some of the series, recession indicators are not available for the last
few months, which caused plotting errors. This patch adds code to fill in
missing indicators with the most recent value.
Shink margins in unemployment plots

This commit removes the large left and right margins from the unemployment
plots. Those margins make sense when plotting past series (so that the date
label fits in the graph), but recently we've started to present only the most
recent graph.