the 1 x 2 vector |yrlim|.  This
% can be used to create an output dataset that spans more or fewer years
% than the input.
%
% |[xg, yr] = reshapetimeseries(t, x, 'pivotdate, [mon day])| set the pivot
% date where the dataset wraps from one year to the next.  By default this
% is [1 1], indicating that each new column of the output |xg| starts on
% Jan 1 of the corresponding year in vector |yr|.
%
% |[xg, yr, tmid] = ...| returns the additional output, |tmid| holding
% datetimes corresponding to the rows of