Big merge from experimental to bleeding edge.

tests/corelib/queue_single_test.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.
+
+main() {
+  Queue<int> queue1 = new Queue<int>();
+  queue1.add(42);
+  Queue queue2 = new Queue();
+  queue2..add(11)
+      ..add(12)
+      ..add(13);
+  Queue queue3 = new Queue();
+
+  Expect.equals(42, queue1.single);
+  Expect.throws(() => queue2.single, (e) => e is StateError);
+  Expect.throws(() => queue3.single, (e) => e is StateError);
+}