INT-3248 Suppress HeaderChannelRegistry Warning

Remove warning from BFCR if there is no HeaderChannelRegistry in
the bean factory. Change the log to DEBUG and remove the stack
trace.

Instead, update the Exception message when a channel name can't be
resolved to a channel to indicate that there is no registry.

JIRA: https://jira.springsource.org/browse/INT-3248
INT-3241: Upgrade Gradle and some dependencies

JIRA: https://jira.springsource.org/browse/INT-3241
INT-3240: i-c-a-parser: Fix gen. MessageSource Id

JIRA: https://jira.springsource.org/browse/INT-3240

Spring Integration 3.0 introduced registration of `MessageSource`s as beans
with an `id` based on the adapter `id` or, as a fallback, generated from
the `MessageSource` class name and the suffix `.source`.
But since that bean wasn't registered as a bean with the generated name (because the suffix was added),
subsequent elements get the same source bean name. This meant that
several anonymous `inbound-channel-adapter` with the same type (`file:`, `ftp:`, `twitter:` etc.)
caused an issue, when the same `MessageSource` bean was used by several `SourcePollingChannelAdapter` beans.

Fix the issue for fallback name generation by using the `SourcePollingChannelAdapterFactoryBean` class name.
Since that is registered, the source will always get a unique name, regardless of whether an id is provided.
INT-3253: Eliminate EasyMock Dependency

JIRA: https://jira.springsource.org/browse/INT-3253

INT-3253 Polishing

Use the mockito test runner to initialize the mocks.
INT-3246: MessageHandlingException Refactoring

JIRA: https://jira.springsource.org/browse/INT-3246

INT-3246: Add description to usage of MHException

Deprecate `MessageRejectedException` constructor

INT-3246: Remove `MessageHandlingException` class
INT-3254: AMQP inbound-gateway: add reply-timeout

JIRA: https://jira.springsource.org/browse/INT-3254

Attribute was missing from the namespace causing issues
with long-running consumers with async handoff.

Also fix typo in http, ampq and core schemas.
Improve JMS Test

Loop sleeping 100ms for up to 10s instead of a hard sleep of 1s.

Stop the gateway in a finally block.
INT-3257 Make AggXmlMValidationEx more convenient

JIRA: https://jira.springsource.org/browse/INT-3257