Kad unit tests:

- Port KBSTest from i2p.zzz.kademlia branch
  - Fix RandomTrimmer so it always returns true, so it may be used
    as the trimmer in the unit tests

core/java/src/net/i2p/kademlia/RandomTrimmer.java

@@ -26,6 +26,7 @@ public class RandomTrimmer<T extends SimpleDataStructure> implements KBucketTrim
         if (sz < _max)
             return true;
         T toRemove = e.get(_ctx.random().nextInt(sz));
-        return kbucket.remove(toRemove);
+        kbucket.remove(toRemove);
+        return true;
     }
 }