Collected Rexster distributed graph test changes

This commit builds against version 2.5.0-SNAPSHOT the
distributed-graph branch of the Rexster repository.  It won't compile
with Rexster master.

This commit is buggy.  At the time I write this message, I'm debugging
an infinite busywork behavior in and around JGroups connection
selection on Titan + BDB that manifests with stack traces like:

"main" prio=10 tid=0x00007f108800a000 nid=0x345 runnable [0x00007f108e1da000]
   java.lang.Thread.State: RUNNABLE
        at java.util.concurrent.ConcurrentHashMap$HashIterator.advance(ConcurrentHashMap.java:1345)
        at java.util.concurrent.ConcurrentHashMap$HashIterator.<init>(ConcurrentHashMap.java:1327)
        at java.util.concurrent.ConcurrentHashMap$ValueIterator.<init>(ConcurrentHashMap.java:1380)
        at java.util.concurrent.ConcurrentHashMap$Values.iterator(ConcurrentHashMap.java:1449)
        at java.util.AbstractCollection.toArray(AbstractCollection.java:137)
        at com.tinkerpop.rexster.client.HintedRexsterClient$RexsterConnections.getAt(HintedRexsterClient.java:421)
        at com.tinkerpop.rexster.client.HintedRexsterClient.nextRoundRobinConnection(HintedRexsterClient.java:261)
        - locked <0x00000000d0c3e5a0> (a com.tinkerpop.rexster.client.HintedRexsterClient$RexsterConnections)
        at com.tinkerpop.rexster.client.HintedRexsterClient.access$400(HintedRexsterClient.java:48)
        at com.tinkerpop.rexster.client.HintedRexsterClient$RexsterConnections.best(HintedRexsterClient.java:459)
        at com.tinkerpop.rexster.client.HintedRexsterClient.sendRequest(HintedRexsterClient.java:285)
        at com.tinkerpop.rexster.client.HintedRexsterClient.execute(HintedRexsterClient.java:174)

The main thread constantly makes progress and pegs a cpu at 100%, it
just never completes execution of a statement.