Streaming: configurable response when over connection limits (ticket #2145)

Drop when way over limits.
Default to HTTP 429 for HTTP Server tunnels
Increase recently-closed cache size

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 = 5;
+    public final static long BUILD = 6;
 
     /** for example "-test" */
     public final static String EXTRA = "";