INT-3266 Java 6 Compiler Compatibility

- ((CachingSessionFactory<?>.CachedSession) session).dirty();
+ ((CachingSessionFactory.CachedSession) session).dirty();

Failed to compile with Java6 (compiles ok with Java7 with
sourceCompatibility=1.6).
INT-3244 Fix RedisMEssageStoreTest Race Condition

JIRA: https://jira.springsource.org/browse/INT-3244
INT-3249: property-placeholder for log-c-a Level

JIRA: https://jira.springsource.org/browse/INT-3249
INT-2688 Add header-type to xpath-header-enricher

JIRA: https://jira.springsource.org/browse/INT-2688
JIRA: https://jira.springsource.org/browse/INT-3237

Doc Polishing.
INT-3273 Fix Tests For Spring AMQP 1.3.x

Some mocking changes are needed to support changes in Spring-AMQP.

Note: Needs Spring AMQP with the fix for AMQP-364 Applied.

JIRA: https://jira.springsource.org/browse/INT-3273