%Display a status/progress bar and inform about the elapsed
%as well as the remaining time (linear estimation).
%
%Synopsis:
%
%  f=statusbar
%     Get all status/progress bar handles.
%
%  f=statusbar(title)
%     Create a new status/progress bar. If title is an empty
%     string, the default 'Progress ...' will be used.
%
%  f=statusbar(title,f)
%     Reset an existing status/progress bar or create a new
%     if the handle became invalid.
%
%  f=statusbar(done,f)
%     For 0 < done < 1, update the progress bar and the elap-
%     sed time. Estimate the remaining time until completion.
%     On user abort, return an empty handle.
%
%  v=statusbar('on')
%  v=statusbar('off')
%     Set default visibility for new statusbars and return
%     the previous setting.
%
%  v=statusbar('on',f)
%  v=statusbar('off',f)
%     Show or hide an existing statusbar and return the last
%     visibility setting.
%
%  delete(statusbar)
%     Remove all status/progress bars.
%
%  drawnow
%     Refresh all GUI windows.
%
%Example:
%
%     f=statusbar('Wait some seconds ...');
%     for p=0:0.01:1
%        pause(0.2);
%        if isempty(statusbar(p,f))
%           break;
%        end
%     end
%     if ishandle(f)
%        delete(f);
%     end

%        Marcel Leutenegger