Add JavaDocs for RouterSpec and ACMH Specs

Polishing
Add JavaDocs for end-user API

Fix `AggregatorSpec.processor` issue with `method`

JavaDocs for some `IntegrationFlowDefinition` methods

Polishing

Add `.travis.yml`
More JavaDocs

Polishing
HeaderEnricherSpec, RLRS JavaDocs; HES Fixes

- Add JavaDocs for HeaderEnricherSpec, RecipientListRouterSpec.
- Add missing overloaded methods for map-based `header` methods with an `override` parameter.
- Remove unused generic parameter from `headerChannelsToString`.
- Add Spring stylesheet to put a box around `<pre class="code" />`.

Polishing
Fix `stylesheet.css` for Java 8
MessageSource JavaDocs

MessageProducerSpec JavaDocs

Polishing
JavaDocs for `IntegrationFlowDefinition`
AMQP Remaining JavaDocs

JMS JavaDocs

Polishing
The remaining `IntegrationFlowDefinition` JavaDocs
JavaDocs for the `core` and `support` packages
[artifactory-release] Release version 1.0.0.RELEASE
[artifactory-release] Next development version
Fix `build.gradle` to correct repository links
GH-9: Fix DslRecipientListRouter Recipients Order

Fixes: https://github.com/spring-projects/spring-integration-java-dsl/issues/9

Since `RecipientListRouter` assumes that recipients should receive message in that order in which they have been added,
the logic with `Map` for each recipient type in the `DslRecipientListRouter` isn't correct.

* Change it to the `List<Tuple2<?, ?>>` and do appropriate logic during iteration saving an order.
* Add `requiresReply = true` for those gateway `Spec`s, which are based on those XML components which provide that option as `true` by default.
* Add more `.recipient()` methods to the `RecipientListRouterSpec`

GH-9 Polishing