March 4 2022; Build 1.60

Fix recent (1.59) bug in processing with !GDENSE qualifier.
Fix recent (1.58) bug reporting labels of class levels in .ess/.etb files

From build 1.58, if Echidna is invoked with no arguments, it enters
a MenuMode with options to and edit an existing command file,
create a command file based on a data file (with variable labels)
and the command file. This will allow Mac users to use Finder.

From build 1.59, processing time for large (less sparse) models has been improved (reduced) by up to 60%.