INT-3138: add `awaitTermination` to delayer tests

`DelayerHandlerRescheduleIntegrationTests` fail sometimes
on asserts. Looks like `context.destroy()` works very slow
and `<delayer>` manages to send delayed Messages

JIRA: https://jira.springsource.org/browse/INT-3138
INT-3092, INT-3042: Doc: Jacksons, Resequencer

JIRA: https://jira.springsource.org/browse/INT-3042
https://jira.springsource.org/browse/INT-3092
INT-3120: Remove `Accept-Charset` from Response

`StringHttpMessageConverter` adds `Accept-Charset` header by default.
By RFC 2616 `Accept-Charset` is a Request header,
so it won't be presented in the response.

Turn off `writeAcceptCharset` in the `HttpRequestHandlingEndpointSupport`.

JIRA: https://jira.springsource.org/browse/INT-3120
INT-2117: Test that trim() Works in the AMMR

* `AbstractMappingMessageRouter#addChannelFromString` uses
`StringUtils.tokenizeToStringArray`, so it's enough to check it from test.

JIRA: https://jira.springsource.org/browse/INT-2117
INT-3117: Add r-c & r-t Attrs. to Chain Gateways

* Add `reply-channel` and `reply-timeout` to `<gateway>` within `<chain>`
* Add appropriate asserts to `ChainParserTests`

JIRA: https://jira.springsource.org/browse/INT-3117
INT-3024: Add <poller> to mongodb:o-c-adapter

In addition add `<request-handler-advice-chain>`

JIRA: https://jira.springsource.org/browse/INT-3024
INT-2739: StoredProc: 'row-mapper' as a Bean Ref

* Convert `row-mapper` attribute of stored procedure components
to bean reference
* Class name is also supported for backward compatibility

JIRA: https://jira.springsource.org/browse/INT-2739
INT-3027: Headers Enrichment for <enricher>

* Add `<header>` sub-element to `<enricher>`
* Refactoring to `EnricherParser`
* Add Headers Enrichment logic to `ContentEnricher`
* Add tests
* What's new and Content Enricher's `<header>` note

JIRA: https://jira.springsource.org/browse/INT-3027
INT-3098 TCP Suppress Error Log on Normal Close

Net connections suppress error logs, NIO connections did not.