Move a bunch of src/ files into subdirectories.

lib/src/runner/vm_listener.dart

 // Copyright (c) 2015, 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.
 
-library unittest.vm_listener;
+library unittest.runner.vm_listener;
 
 import 'dart:isolate';
 import 'dart:async';
 
-import 'declarer.dart';
-import 'remote_exception.dart';
-import 'suite.dart';
-import 'test.dart';
-import 'utils.dart';
+import '../backend/declarer.dart';
+import '../backend/suite.dart';
+import '../backend/test.dart';
+import '../util/remote_exception.dart';
+import '../utils.dart';
 
 /// A class that runs tests in a separate isolate and communicates the results
 /// back to the main isolate.
 class VmListener {
   /// The test suite to run.
   final Suite _suite;
 
   /// Extracts metadata about all the tests in the function returned by
   /// [getMain] and sends information about them over [sendPort].
   ///
@@ skipping 81 matching lines @@
       sendPort.send({
         "type": "error",
         "error": RemoteException.serialize(
             asyncError.error, asyncError.stackTrace)
       });
     });
 
     liveTest.run().then((_) => sendPort.send({"type": "complete"}));
   }
 }