Issue: SPR-13066

Issue: SPR-11512

Issue: SPR-13065

This commit also introduces a cache for attribute alias metadata.

Issue: SPR-11512

Issue: SPR-11512

Issue: SPR-13064

Issue: SPR-11512

Reinstate a variant of the `WebContentGenerator.checkAndPrepare` method
for projects that are using it.

This variant is now marked as deprecated.

Issue: SPR-11792

Issue: SPR-11512

This change ensures that the deprecated UserSessionRegistry is still
used if configured.

Before this commit the object that #this would refer to in
nested expressions within projection/selection clauses was always
the root context object. This was incorrect as it should be the
element being projected/selected over. This commit introduces
a scope root context object which is set upon entering a new
scope (like when entering a projection or selection). Any
object. With this change this kind of expression now behaves:

where #this is the element of list1. Unqualified references
are also resolved against this scope root context object.

Issues: SPR-10417, SPR-12035, SPR-13055

This commit introduces a test that will fail if SynthesizedAnnotation is
not public as is required by the contract for getProxyClass() in
java.lang.reflect.Proxy.

Issue: SPR-13057

Issue: SPR-13060

Issue: SPR-13056

Issue: SPR-12207

This commit introduces support for asynchronous return values thanks
to the new AsyncHandlerMethodReturnValueHandler interface. Out of
the box support for ListenableFuture is also provided.

Issue: SPR-12168

Includes an optimization for simple ByteBuffer duplication.

Issue: SPR-13056

Commit 3d86f15a added a lot of new feature in AbstractPropertyAccessor
shared by both DirectFieldAccessor and BeanWrapperImpl. This makes this
abstract class harder to implement for others having simpler use cases.

It turns that Spring Data has such use case; this commit split these new
features in a dedicated new base class, leaving AbstractPropertyAccessor
untouched.

Issue: SPR-12805