Allow users to override logical name of channel.

Conflicts:
	core/src/main/java/net/sf/hajdbc/distributed/jgroups/JGroupsCommandDispatcherFactory.java
	core/src/site/changes.xml
Add debug logging.
Dependency refresh.

Conflicts:
	pom.xml
	src/test/java/net/sf/hajdbc/SimpleTest.java
Fix NPE when previous coordinator is restarted.
Refactor command dispatcher logic using channel that does not discard its own messages.
Code cleanup.