allow single character variable/argument names (used a lot in Parsing.py, for example)

pylintrc

@@ -102,10 +102,10 @@ method-rgx=[a-z_][a-z0-9_]{2,30}|visit_[A-Za-z]+$
 attr-rgx=[a-z_][a-z0-9_]{2,30}$
 
 # Regular expression which should only match correct argument names
-argument-rgx=[a-z_][a-z0-9_]{2,30}$
+argument-rgx=[a-z_][a-z0-9_]{0,30}$
 
 # Regular expression which should only match correct variable names
-variable-rgx=[a-z_][a-z0-9_]{2,30}$
+variable-rgx=[a-z_][a-z0-9_]{0,30}$
 
 # Regular expression which should only match correct list comprehension /
 # generator expression variable names