anchor.diff:  List<int> urlEncode(String s) {
     int i, p, q;
     var ol = new List<int>();
  -  List<int> il = utf.encodeUtf8(s);
  +  List<int> il = UTF8.encode(s);
     for (i = 0; i < il.length; i++) {
       if (il[i] == 0x20) { ol.add(0x2b);  // convert sp to +
       } else if (il[i] == 0x2a || il[i] == 0x2d || il[i] == 0x2e || il[i] == 0x5f) { ol.add(il[i]);  // do not convert
  
positive.code:   Feb. 2013, Revised to incorporate revised dart:io library.
    March 2013, API changes (String and HttpResponse) fixed
    July 2013, Modified main() to ruggedize.
    Aug. 2913, API change (removed StringDecoder and added dart:convert) fixed
  */
  
  import "dart:async";
  import "dart:io";
  import "dart:convert";
  import "dart:utf" as utf;
  
  final HOST = "127.0.0.1";
  final PORT = 8080;
  
negative.code:      else { ol.add(s[i].codeUnitAt(0));
       }
     }
    return UTF8.decode(ol);
  }
  
  // URL encoder encodes string into url encoded utf-8 bytes
  