Move a bunch of src/ files into subdirectories.

lib/src/deprecated/simple_configuration.dart

 // Copyright (c) 2013, 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.simple_configuration;
+library unittest.deprecated.simple_configuration;
 
 import 'test_case.dart';
 import 'configuration.dart';
 
 /// This is a stub class used to preserve compatibility with unittest 0.11.*.
 ///
 /// It will be removed before the next version is released.
 @deprecated
 class SimpleConfiguration extends Configuration {
   bool throwOnTestFailures = true;
   SimpleConfiguration() : super.blank();
 
   String formatResult(TestCase testCase) => "";
 }