cvar: a pedestrian variable name checker

CVAR checks the names of
- variable(s) in the current workspace
- variable(s) not yet defined
for conflicts with known
- ML stock functions
- built-in functions
- user defined functions

cvar; % check current variables in the callers workspace...
cvar a b pi; % check validity of input...

see
>> help cvar;
and the screenshot for information and examples for this rather self-explanatory snippet