Added i18n skeleton API for message_formatting

tests/lib/i18n/date_format_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.
+ */
+
+#library('date_format_test');
+
+#import('../../../lib/i18n/date_format.dart');
+#import('../../../lib/unittest/unittest.dart');
+
+/**
+ * Tests the DateFormat library in dart.
+ */
+
+main() {
+  test('Date formatting', () {
+    var date_format = new DateFormat.fullDate();
+    Date date = new Date.now();
+    // TODO(efortuna): Change the expectation once we have a functioning date
+    // formatting class.
+    Expect.stringEquals(date.toString(), date_format.format(date));
+    
+    date_format = new DateFormat("hh:mm:ss");
+    Expect.stringEquals(date.toString(), date_format.format(date));
+  });
+
+  test('Date parsing', () {
+    var date_format = new DateFormat.fullDate();
+    Date date =  new Date.now();
+    // TODO(efortuna): Change the expectation once we have a functioning date
+    // formatting class.
+    Expect.stringEquals(date_format.parse(date.toString()), date.toString());
+  });
+}