INT-2918: Add Redis Outbound Command Gateway

JIRA: https://jira.springsource.org/browse/INT-2918

INT-2918: Improvement according PR comments

INT-2918: Polishing according PR comments

Minor Doc Polishing

INT-2918: Change `notNull` message

Polishing
INT-3345 Update Spring-AMQP to 1.3.1.RELEASE

JIRA: https://jira.spring.io/browse/INT-3345