Add pub (and by extension YAML) to the SDK.

utils/pub/sdk/pub.bat

Index: utils/pub/sdk/pub.bat
diff --git a/utils/pub/sdk/pub.bat b/utils/pub/sdk/pub.bat
new file mode 100644
index 0000000000000000000000000000000000000000..bc47b4953f1b1d6d9e5e65cb450da32307afcdce
--- /dev/null
+++ b/utils/pub/sdk/pub.bat
@@ -0,0 +1,18 @@
+@echo off
+REM Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+REM for details. All rights reserved. Use of this source code is governed by a
+REM BSD-style license that can be found in the LICENSE file.
+
+REM Run pub.dart on the Dart VM. This script assumes the Dart SDK's directory
+REM structure.
+
+set SCRIPTPATH=%~dp0
+
+REM Does the string have a trailing slash? If so, remove it.
+if %SCRIPTPATH:~-1%==\ set SCRIPTPATH=%SCRIPTPATH:~0,-1%
+
+REM Canonicalize the direction of the slashes.
+set script=%*
+set script=%script:\=/%
+
+"%SCRIPTPATH%\dart.exe" "%SCRIPTPATH%\..\util\pub\pub.dart" %script%