Issue: SPR-10763

Issue: SPR-10597

Port the latest unreleased UndeclaredThrowableStrategy implementation
from cglib to fix a memory-leak present in v3.

Issue: SPR-10709

Issue: SPR-10627

Issue: SPR-9186

Issue: SPR-10752

The resolver for /user/{username} prefixed destinations is now
more explicitly designed to store queue suffixes rather than session
id's, which is what we happen to use as queue suffixes.

This allows something other than the sessionId to be used without
having to change many places. It also enables applications to
construct destinations with user-specific queue suffixes without
making assumptions about what's used for queue suffixes. For
example a controller may construct a map with subscription destinations
and send that down to the client.

Issue: SPR-10587

# By Oliver Gierke
* SPR-10678:
  Fixed potential NPE in SharedEntityManagerCreator

Fix SharedEntityManagerCreator.createSharedEntityManager to correctly
forward an empty array in case that EntityManagerFactoryInfo returns
null from getEntityManagerInterface().

Previously the var-args invocation had turned null into an array with
a null value which caused a NullPointerException in the call to
Proxy.newProxyInstance() further down the call stack.

Issue: SPR-10678

Reduce INFO level startup logging to DEBUG

Issue: SPR-10758

Update ConfigurationClassParser to resolve any ${} placeholders from
@ImportResource values.

Issue: SPR-10686

Added 'processExternalEntities' property to the JAXB2Marshaller, which
indicates whether external XML entities are processed when
unmarshalling.

Default is false, meaning that external entities are not resolved.
Processing of external entities will only be enabled/disabled when the
Source} passed to #unmarshal(Source) is a SAXSource or StreamSource. It
has no effect for DOMSource or StAXSource instances.

The following commit in 3.2.3 had a side effect on CNVR:
https://github.com/SpringSource/spring-framework/commit/aaded7e30b06cc70a354856a2288acd04045b673

It appears that CNVR doesn't treat a request for "*/*" differently
from a request that does not request content types. Both should be
interpreted as "any content type is acceptable". This fix ensures
that CNVR treats these two cases the same way.

Issue: SPR-10683

Issue: SPR-10704

Issue: SPR-10621

Also remove Servlet 3 bridge classes no longer needed since Spring
Framework 4 compiles with the Servlet 3 API. That means applications
may need to run tests with the Servlet 3 API jar although
technically they don't have to run with that in production.

Issue: SPR-10673

Issue: SPR-10721

The new UserDestinationMessageHandler resolves messages with
destinations prefixed with "/user/{username}" and resolves them into a
destination to which the user is currently subscribed by appending the
user session id.

For example a destination such as "/user/john/queue/trade-confirmation"
would resolve "/trade-confirmation/i9oqdfzo" assuming "i9oqdfzo" is the
user's session id.

Remove base class for STOMP-related message handler classes
(AbstractSimpMessageHandler), polish subclasses and fix issues with
more significant updates to STOMP broker relay.

Introduce base class for SubscribableChannel implementations providing
consistent logging for all channel implementations.