AMQP-304 Close Rabbit Connections in Tests

For reference see: https://jira.springsource.org/browse/AMQP-304

Polishing
Merge pull request #89 from ghillert/AMQP-304
AMQP-302 - Remove Warnings During Build with JDK7

* Add JavaDoc links to build.gradle
* Make deprecation message in *FederatedExchange* more expressive (Add affected version)

AMQP-302 - Code Review Changes
Merge pull request #90 from ghillert/AMQP-302
AMQP-303 - Improve Rules Compliance (Sonar)
Merge pull request #91 from ghillert/AMQP-303
AMQP-305 - Polish Reference Documentation

* Fix Code Highlighting for several code snippets
* Fix/Shorten code snippet lines that are too long
* Ensure that <programlisting/> tags are not wrapped by <para/> tags as this may cause paragraph spacing issues (PDF)
Merge pull request #92 from ghillert/AMQP-305
AMQP-271 Allow Use of Standard CorrelationId Prop

Previously a custom header was used to convey
correlation data.

Provide the option to specify a header name, and
use the correlationId property by default.

Also, previously, to support "chained" application
modules, existing replyTo and correlation data was
pushed onto a "stacked" header and popped off when
receiving the reply.

This complexity was unnecessary because the
RabbitTemplate already maintains state for the
pending reply, so the existing replyTo/correlation
can be maintained there instead of adding it to
the message.

* Add Documentation
  - Add information to the what's new section
  - Add a subsection about message correlation to the main reference doc
Merge pull request #84 from garyrussell/AMQP-271

* garyrussell-AMQP-271:
  AMQP-271 Allow Use of Standard CorrelationId Prop
AMQP-303 Reinstate public Modifier

Several inner interfaces incorrectly had the public modifier
removed.
[artifactory-release] Release version 1.2.0.M1
Revert Version to 1.2.0.BUILD-SNAPSHOT