Fix Occasional Reaper Expiry Test Failure

https://build.spring.io/browse/INT-MJATS41-32/

Also add a test for expiring a group within an aggregator.

Polishing
INT-3384: Rework JMS/XML Module XSD Enumerations

JIRA: https://jira.spring.io/browse/INT-3384

Polishing
Fix Timing in GemFire Delayer Reschedule Test

https://build.spring.io/browse/INT-MEIGHT-JOB1-166
INT-3412 (S)FTP Append, rmdir, Client Access

JIRA: https://jira.spring.io/browse/INT-3412

Initial commit - review only.

TODO:
- SFTP Tests
- Namespace/Adapter support for file append
- Docs

INT-3412 Polishing

- Addressed PR comments
- Completed SFTP implementation
- Added namespace/parser support for `FileExistsMode` (append, etc)
- Added SFTP Tests
- Created Embedded SFTP server for tests (similar to FTP)
- Converted tests that needed a real server to use the embedded server

INT-3412 Docs and Polish (PR Comments)
INT-3402: Late Resolution for Channel Names

JIRA: https://jira.spring.io/browse/INT-3402

* Move `channel name to channel` resolution logic to the action, e.g. `sendReplyMessage`
* Remove resolution logic from `MessagingAnnotation` Processors
* Fix `AggregatorAnnotationPostProcessor` to invoke `handler.afterPropertiesSet()` one more time,
because of `AbstractMethodAnnotationPostProcessor` `this.beanFactory.initializeBean(handler, handlerBeanName)`
* `Filter` annotation: allow `property-placeholder` for the `discardWithinAdvice`
* Fix `EnricherParserTests4-context.xml` duration: use just `0` for the `reply-timeout`

INT-3402: Add `synchronized double check`

INT-3402: Polishing according PR comments

INT-3402: Optimization for `AbstractCorrelatingMH`
INT-2474: MGS: logging Exception at debug level

JIRA: https://jira.spring.io/browse/INT-2474
INT-3455 Orderly Shutdown Improvements

JIRA: https://jira.spring.io/browse/INT-3455

Do not stop schedulers and executors - allows mid-flow
QueueChannels to be drained.

Stop all inbound MessageProducers (that are not OrderlyShutdownCapable).

INT-3455 Polishing; PR Comments

Change deprecate method usage to the new version
INT-3485: Remove final from `AE.stop(Runnable)`

JIRA: https://jira.spring.io/browse/INT-3485

Delegate to doStop() instead of overriding stop() directly

Delegated call to doStop() rather than stop(), added author tag and added unit test for custom doStop(runnable)

Polishing
INT-3479 Improve ServiceActivatingHandler.toString

JIRA: https://jira.spring.io/browse/INT-3479

- Remove null `beanName` in `AbstractStandardMessageHandlerFactoryBean`
- Change `ServiceActivatingHandler.toString()`
- Fix aggregator test timing
INT-3478 SftpPAOnceFileListFilter use getFilename

JIRA: https://jira.spring.io/browse/INT-3478

INT-3478: add test case

Polishing
INT-1197: Add support for WebSockets: client side

JIRA: https://jira.spring.io/browse/INT-1197
INT-1197: Add JavaDocs and some polishing
Further changes

* Upgrade to SF 4.1
* Rename `SubProtocolHandlerContainer` to the `SubProtocolHandlerRegistry`
* Add `MessageConverter` support to the adapters
* Add `ClientWebSocketContainer.openConnectionException` to be thrown on `getSession` request
* Add `ClientWebSocketContainer.connectionLatch` to wait the connection establishing on first request.
Since the WebSocket connection process is run in the separate Thread, we need to wait it from the first `message send` do not lose the message, if connection hasn't been established yet.
INT-1197: Add `PassThruSubProtocolHandler`

Add `StompIntegrationTests`
INT-1197: Polishing according PR comments
INT-1197: Use SockJs from tests

Fix other detected vulnerabilities
INT-1197: `@Gateway` with `@MessageMapping` test
INT-1197: PR comments

Skip non `SimpMessageType.MESSAGE` to send to the `outputChannel` from `WebSocketInboundChannelAdapter`