- Replace fragile dependence on the resulting parse tree with a more
resilient usage of the value stack to build condition objects as the
rules are parsed.  
- Break the condition and pojo logic up so it is
possible to reuse the condition parsing with multiple field evaluation
mechanisms.  
- Add support to PojoEvaluator to determine ahead of time if
a given condition will work with a class with the
getUnsupportedIdentifiers() method.