Second step in simplifying the ReplicationBroker class.


ReplicationBroker.java
Moved session field to ConnectedRS.
Removed field protocolVersion (useless, superseded by ConnectedRS)
Reworked ConnectedRS class: removed connected field.
In ReplicationServerInfo, added setServerURL() + internally stored a RSInfo object + changed connectedDSs from List to Set.
Used 
Improved javadocs + removed comments redundant with javadocs.

ComputeBestServerTest.java:
Consequence of the change to ReplicationBroker.ReplicationServerInfo ctor.

UnbindOperationTestCase.java, ReplicationDomain.java:
Code cleanup.