Add HTTP/1.0 support and simplify persistent connections handling

tests/standalone/src/io/HttpClientTest.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #import("dart:io");
 #import("dart:uri");
 #import("dart:isolate");
 
 void testGoogle() {
   HttpClient client = new HttpClient();
   var conn = client.get('www.google.com', 80, '/');
 
   conn.onRequest = (HttpClientRequest request) {
-    request.keepAlive = false;

[Anders Johnsen, 2012/04/13 09:02:38]

Since you have changed keepAlive to be on by default, should we do something
else in this test?

[Søren Gjesse, 2012/04/13 10:58:31]

I don't think so. I don't even know why it was here in the first place.

     request.outputStream.close();
   };
   conn.onResponse = (HttpClientResponse response) {
     Expect.isTrue(response.statusCode < 500);
     response.inputStream.onData = () {
       response.inputStream.read();
     };
     response.inputStream.onClosed = () {
       client.shutdown();
     };
   };
   conn.onError = (error) => Expect.fail("Unexpected IO error");
 }
 
 void testGoogleUrl() {
   HttpClient client = new HttpClient();
 
   void testUrl(String url) {
     var conn = client.getUrl(new Uri.fromString(url));
 
     conn.onRequest = (HttpClientRequest request) {
-      request.keepAlive = false;
       request.outputStream.close();
     };
     conn.onResponse = (HttpClientResponse response) {
       Expect.isTrue(response.statusCode < 500);
       response.inputStream.onData = () {
         response.inputStream.read();
       };
       response.inputStream.onClosed = () {
         client.shutdown();
       };
@@ skipping 30 matching lines @@
 }
 
 void main() {
   // TODO(sgjesse): Making empty www.google.com requests seems to fail
   //on buildbot.
   //testGoogle();
   //testGoogleUrl();
   testInvalidUrl();
   testBadHostName();
 }