AbstractAdvisingBeanPostProcessor uses target class check for existing proxy but checks against actual exposed object otherwise (catching introductions)

Issue: SPR-11725
Polishing
AbstractAutoProxyCreator and AbstractAdvisingBeanPostProcessor consistently not considering configuration callbacks and internal language interfaces as reasonable proxy interfaces

Issue: SPR-11715
Polishing
Simplify STOMP broker relay integration test

This change simplifies the implementation of the "test" EventPublisher
and MessageHandler used in the STOMP broker relay integration tests.
The updated implementations use a time-limted poll on a BlockingQueue.
Fix issue in STOMP broker relay integration test
Fix one more issue in STOMP broker relay int test
Fix STOMP broker relay int test issue

Avoid dependency on order in which expected messages are received.
Polishing
Fix DefaultSubscriptionRegistry when using pattern destinations

DestinationCache is now used for both plain and pattern
destinations. It stores internally the subscriptions map for each
cached destination. Subscriptions are initially created when there
is no cache for the requested destination, and are updated when
subscriptions change.

Issue: SPR-11657
Add cache limit to DefaultSessionRegistry and polish

Issue: SPR-11657
Split destination cache into access vs update

Issue: SPR-11657
Fix Cacheable javadoc

This commits fixes a confusing phrasing of Cacheable javadoc that
mentioned explicitly that the method signature is used to compute the
key for the cache.

Issue: SPR-11736
Spring Framework build uses Reactor 1.1 GA now, getting rid of last remaining pre-GA dependency
(cherry picked from commit 27b2ed1)
JRubyScriptUtils defensively handles null Nodes in findClassNode (fails against JRuby 1.7.12 otherwise)

Issue: SPR-11747
Upgraded to Gradle 1.12 and updated several dependencies to latest maintenance releases
Integrate animal sniffer

Animal sniffer provides tools to assist verifying that classes
compiled with a newer JDK are compatible with an older JDK.

This integratesthe latest version of the tool (1.11) that
permits the use of custom annotations. Added @UsesJava7,
@UsesJava8 and @UsesSunHttpServer and annotated the few places
where we rely on a specific environment.

The verification process can be invoked by running the 'sniff'
task.

Issue: SPR-11604

polishing
Fix Javadoc typo
Update log level

Issue: SPR-11673
Log STOMP ERROR frames at error level

Issue: SPR-11673