Fix bug that ignored custom json prefix

Issue: SPR-10817
Added Java 8 compliant @Schedules container annotation for @Scheduled

Issue: SPR-10532
Introduced  DefaultParameterNameDiscoverer which checks JDK 8's standard reflection first and then falls back to ASM-based debug symbol analysis

Also, StandardReflectionParameterNameDiscoverer calls "Parameter.isNamePresent()" now to return null (and pass on to the next discoverer) if no JDK 8 parameters are available. Note that this requires OpenJDK 8 b100 or higher to compile now.

Issue: SPR-10532
XStreamMarshaller exposes public marshal methods with DataHolder parameter

Also splitted buildXStream into constructXStream and configureXStream now.

Issue: SPR-10421
Consistent use of varargs, consistent template method order
Added XStream CatchAllConverter

Added XStream CatchAllConverter that supports all classes, but throws
exceptions for (un)marshalling.

Main purpose of this class is to register this converter as a catchall
last converter with a normal or higher priority in addition to
converters that explicitly  support the domain classes that should be
supported. As a result, default XStream  converters with lower
priorities and possible security vulnerabilities do not get invoked.
Add test with @Schedules container annotation

Issue: SPR-10532
Added reference to CatchAllConverter

Added reference to CatchAllConverter in both javadoc and reference docs.

Issue: SPR-10821
Fix typo in reference docs
Merge pull request #328 from lonre/typo-fix

# By Lonre Wang
* typo-fix:
  Fix typo in reference docs
Avoid use of repeated @Scheduled in tests

Commented out severalFixedRatesWithRepeatedScheduledAnnotation() until
we have full Java 8 support in the IDEs (e.g., Eclipse).

Issue: SPR-10532
Polish WebSocketSession

Update methods available on WebSocketSession interface.
Introduce DelegatingWebSocketSession interface.
Fix configuration issues in DefaultSockJsService
Add HandshakeInterceptor

A HandshakeInterceptor can be used to intercept WebSocket handshakes
(or SockJS requests where a new session is created) in order to
inspect the request and response before and after the handshake
including the ability to pass attributes to the WebSocketHandler,
which the hander can access through
WebSocketSession.getHandshakeAttributes()

An HttpSessionHandshakeInterceptor is available that can copy
attributes from the HTTP session to make them available to the
WebSocket session.

Issue: SPR-10624
Support 'empty' StreamSource in Jaxb2Marshaller

Added support for StreamSources that do not have a InputStream or
Reader, but do have a System ID.

Issue: 10828
Add canRead/Write to MarshallingHttpMessageConverter

Issue: SPR-10463
Integration tests for the broker relay
Publish events about broker's availability

Components that are using a StompBrokerRelayMessageHandler may want
to know whether or not the broker's unavailable. If they're sending
messages to the relay via an asynchronous channel there's currently
no way for them to find this out.

This commit enhances StompBrokerRelayMessageHandler to publish
application events when the broker's availability changes:
BrokerBecameAvailableEvent and BrokerBecameUnavailableEvent.
Irrespective of the number of relay sessions only a single event is
published for each change in the broker's availability.
Add reconnect logic to the relay's system session

Upgrade to Reactor snapshot builds to take advantage of TcpClient's
reconnect support that was added post-M1. Now, the system relay session
will try every 5 seconds to establish a connection with the broker, both
when first connecting and in the event of subsequently becoming
disconnected.

A more sophisticated reconnection policy, including back off and
failover to different brokers, is possible with the Reactor API. We may
want to enhance the relay's reconnection policy in the future.

Typically, a broken connection is identified by the failure to forward
a message to the broker. As things stand, the message id then discarded.
Any further messages that are forwarded before the connection's been
re-established are queued for forwarding once the CONNECTED frame's been
received. We may want to consider also queueing the message that failed
to send, however we would then need to consider the possibility of the
message itself being what caused the broker to close the connection
and resending it would simply cause the connection to be closed again.