cobcd.py now accepts the cob_field f_ name in VARIABLE_STRING.  It can also tolerate ANY NUMERIC and ANY LENGTH
variables, although it doesn't attempt to display them.

This is the Rubicon.  After this release, I am going to switch over to using Simons cob_get... and cob_put... routines,
which accept a pointer to the f_ cob_field variable and accept or produce text strings for the specified variable.