(..., 'center', center)
%  [...] = ensemble2bnd(..., 'prc', prc)
%  [...] = ensemble2bnd(..., 'alpha', alphaval)
%  [...] = ensemble2bnd(..., 'tlim', tlim)
%  [...] = ensemble2bnd(..., 'cmap', colors)
%  [...] = ensemble2bnd(..., 'axis', hax)
%  [...] = ensemble2bnd(..., 'whisker', w)
%
%% Description
%
% |[A, h] = ensemble2bnd(x,y)| calculates the mean and upper/lower bounds
% of y at each x-coordinate.  The x data should be a vector array, and y is
% a nx x ny x nens array, where nx corresponds to the num