Changed the SIMPLE-VAR-PARSER to accept NIL as a variable name.
Changed the SIMPLE-VAR-PARSER to accept NIL as a variable name.

vtomole/SICL,clasp-developers/SICL,clasp-developers/SICL,vtomole/SICL,vtomole/SICL,clasp-developers/SICL,vtomole/SICL,clasp-developers/SICL