Streaming: Increase MTU for ratchet (proposal 155)

Set MTU in receiveConnection() for inbound connections
Cleanup CDR.isAckOnly()
Only call now() in MOS for debugging
Set receive.streamActive stat to 1, not 0

router/java/src/net/i2p/router/RouterVersion.java

@@ -18,7 +18,7 @@ public class RouterVersion {
     /** deprecated */
     public final static String ID = "Monotone";
     public final static String VERSION = CoreVersion.VERSION;
-    public final static long BUILD = 2;
+    public final static long BUILD = 3;
 
     /** for example "-test" */
     public final static String EXTRA = "";