Merge branch 'ssuackdelay' into 'master'

SSU: Reduce ack delay to minimize addition to measured RTT

See merge request i2p-hackers/i2p.i2p!57

router/java/src/net/i2p/router/transport/udp/PeerState.java

@@ -2297,7 +2297,7 @@ public class PeerState {
     private class ACKTimer extends SimpleTimer2.TimedEvent {
         public ACKTimer() {
             super(_context.simpleTimer2());
-            long delta = Math.min(_rtt/2, ACK_FREQUENCY);
+            long delta = Math.max(10, Math.min(_rtt/6, ACK_FREQUENCY));
             if (_log.shouldDebug())
                 _log.debug("Sending delayed ack in " + delta + ": " + PeerState.this);
             schedule(delta);