user_sub called if first word in command line not recognized

[millerta]

Change to report error, command not found.
Otherwise, if something is written into user_sub, it will be called if command not recognized.

Keep user_sub as call if "user_sub" command found.
Add test command to call example (that was in user_sub), this can be added to instructions.
test
will create hex mesh then use cmo_get calls to report values