Revert "tweak: Increase default window size to 128"

This reverts commit 1f55842.

I am experimenting with the library and so need main to be back to what we're actually shipping.

LiteNetLib/NetConstants.cs

@@ -38,7 +38,7 @@ public enum DeliveryMethod : byte
     public static class NetConstants
     {
         //can be tuned
-        public const int DefaultWindowSize = 128;
+        public const int DefaultWindowSize = 64;
         public const int SocketBufferSize = 1024 * 1024; //1mb
         public const int SocketTTL = 255;