Operator - CmpEnumSpecific - exception when comparing object with null

```
Problem - exception in "g.If (g.Local(...)==null)" when type of local variable 
is user type like "class TestClass{}".

You can add check to method "CmpEnumSpecific" in Operator.cs like this:
if (((object)args[0]==null)||((object)args[1]==null)) return stdNone;

```

Original issue reported on code.google.com by `vlad.v...@gmail.com` on 4 Dec 2012 at 3:50
