INT-1834: Register Beans for Annotated Handlers

JIRA: https://jira.springsource.org/browse/INT-1834

The general issue has been raised about `MessageHistory` for annotated endpoints (`@ServiceActivator`, `@Transformer` etc.)

* Register generated `MessageHandler`s as beans with concrete names based on component, method and annotation.
* Add tests and docs

In addition revert the version for JRuby to 1.7.8 as other latests versions have a NPE issue around `System.console()`

Doc Polishing