migration to IBinaryStream interface.

GameRes/ArcFile.cs

@@ -211,6 +211,14 @@ namespace GameRes
             }
         }
 
+        public IBinaryStream OpenBinaryEntry (Entry entry)
+        {
+            var input = OpenSeekableEntry (entry);
+            if (input is IBinaryStream)
+                return input as IBinaryStream;
+            return new BinaryStream (input, entry.Name);
+        }
+
         public ArchiveFileSystem CreateFileSystem ()
         {
             if (m_interface.IsHierarchic)