a less radical proposal for the Query hierarchy

[gavinking]

Competes with #842

This one:

• Adds ofType() and withEntityGraph() to Query, because they're nice.
• Deprecates getResultList() and getResultStream() on Query.
• Adds a new method getResults() returning List<?> on Query, overridden to return List<T> on TypedQuery.
• Introduces QueryReference, without saying it always represents a statement.