i2ptunnel: Retry accept after router soft restart (ticket #2003)

This sends the router restart indication from I2CP router side
to client side to streaming to I2PTunnelServer via
a new streaming exception.

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 = 6;
+    public final static long BUILD = 7;
 
     /** for example "-test" */
     public final static String EXTRA = "";