fixes #221, initial sync*, async, async* implementation

test/codegen/language/async_continue_label_test.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.
+
+import "package:expect/expect.dart";
+import "package:async_helper/async_helper.dart";
+
+// Two loop variables
+test1() async {
+  var r = 0;
+  label:
+  for(var i = 1, j =
+      await /// await_in_init: ok
+                     10; i < 10 && j > 
+      await /// await_in_condition: ok
+                                       -5; j--, i +=
+      await /// await_in_update: ok
+                                                     1) {
+    if (i < 
+        await /// await_in_body: ok
+            5 || j < -5) {
+      continue label;
+    }
+    r++;
+  }
+  Expect.equals(5, r);
+}
+
+// One loop variable
+test2() async {
+  var r = 0;
+  label:
+  for(var i = 
+     await /// await_in_init: ok
+              0; i < 
+     await /// await_in_condition: ok
+                     10; i +=
+     await /// await_in_update: ok
+                              1) {
+    if (i <
+        await /// await_in_body: ok
+            5) {
+      continue label;
+    }
+    r++;
+  }
+  Expect.equals(5, r);
+}
+
+// Variable not declared in initializer;
+test3() async {
+  var r = 0, i, j;
+  label:
+  for(i =
+      await /// await_in_init: ok
+           0; i < 
+      await /// await_in_condition: ok
+                   10; i +=
+      await /// await_in_update: ok
+                            1) {
+    if (i < 
+        await /// await_in_body: ok
+            5) {
+      continue label;
+    }
+    r++;
+  }
+  Expect.equals(5, r);
+}
+
+// Nested loop
+test4() async {
+  var r = 0;
+  label:
+  for(var i = 
+      await /// await_in_init: ok
+              0; i <
+      await /// await_in_condition: ok
+                      10; i+=
+      await /// await_in_update: ok
+                              1) {
+    if (i <
+        await /// await_in_body: ok
+            5) {
+      for (int i = 0; i < 10; i++) {
+        continue label;
+      } 
+    }
+    r++;
+  }
+  Expect.equals(5, r);
+}
+
+test() async {
+  await test1();
+  await test2();
+  await test3();
+  await test4();
+}
+
+main() {
+  asyncStart();
+  test().then((_) => asyncEnd());
+}