DeferredQueryInvocationHandler explicitly closes its EntityManager on garbage collection

Includes javadoc revision covering all supported EntityManager types as of JPA 2.1.

Issue: SPR-11451
Extracted simple MethodInvokingBean as alternative to (and base class for) MethodInvokingFactoryBean

Issue: SPR-11196
Favor ScriptException over SQLException

In ScriptUtils and related classes, SQLExceptions are now caught and
wrapped in ScriptExceptions wherever feasible.

Affected "throws" declarations have also been revised as appropriate.

Issue: SPR-11564