Add a dart library and a dart script for creating version numbers.

tools/version.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.
+
+#import("testing/dart/version.dart");

[kasperl, 2012/10/10 12:21:05]

import "testing/dart/version.dart";

+
+void main() {
+  Version version = new Version("tools/VERSION");

[kasperl, 2012/10/10 12:21:05]

Does this mean that you have to run this script from the top-level directory?
Can you make it independent of that?

+  Future f = version.getVersion();
+  f.then((currentVersion) {
+    print(currentVersion);
+  });
+  f.handleException((e) {
+    print("Could not create version number, failed with: $e");
+    return true;
+  });
+}