fix Hibernate error messages

[gavinking]

Need to patch Hibernate to produce better error messages.

[gavinking]

• Use of aggregate functions sum(), max(), etc, in where clause should be an error
• Use of key(), value(), entry() on a non-Map alias causes an NPE
• subqueries with any/some/all operators must occur on RHS of comparison operator
• Unknown identifier in select results in really ugly error!
• Validate typename in type(p) = Employee