ISPN-4902 Unsupported Class Version Error when running testsuite with JDK6

Update documentation.
Clean up generics a bit
ISPN-4951 Entry Retriever iterator should rethrow caused exception

* Pass along any local throwable to iterator
* If remote node receives throwable propagate that as a response
ISPN-4982 EntryRetriever doesn't filter and convert activated values
properly