Add frog build target on Windows and change frogium and webdriver components to use frog instead ...

frog/scripts/bootstrap/frog.bat

Index: frog/scripts/bootstrap/frog.bat
===================================================================
--- frog/scripts/bootstrap/frog.bat	(revision 0)
+++ frog/scripts/bootstrap/frog.bat	(revision 0)
@@ -0,0 +1,21 @@
+@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 This script provides the entry point for frog on Windows, without having to 
+REM explicitly call python frog.py. It is used on the buildbot and for any 
+REM Windows user of frog.
+
+REM Call frog using python.
+
+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:\=/%
+
+python %SCRIPTPATH%\frog %script%