May 11 2021; Update 1.52

Revised parsing of the model line to resolve a few issues. Hopefully everything else still works.
Revised processing of !A and !I class name lists to resolve some problems. Hopefully all issues are now resolved. If you have build 1.51, I recommend you update it promptly.
Allowed at(Treat,’Alpha’) as model term component alternative to at(Treat,1) where ‘Alpha’ is the name for the first class in Treat.

As always, some repairs create new problems. Do not hesitate to report anything that looks not quite correct (or seriously wrong). Better to check rather than to get caught out.