add script executor

also added a postcompile script to each project to place the outputs in the right folder

fixes #237

scripts/build/place-binary.cmd

@@ -0,0 +1,24 @@
+@echo off
+
+REM Copyright (c) .NET Foundation and contributors. All rights reserved.
+REM Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+set SRC=%1
+
+set SRC=%SRC:/=\%
+
+pushd %~dp0..\..
+set DST=%CD%\artifacts\win7-x64\stage2\bin
+popd
+
+if not exist "%SRC%" goto end
+if not exist "%DST%" goto skip
+
+xcopy /F /Y /I "%SRC%" "%DST%"
+
+goto end
+
+:skip
+echo The destination "%DST%" does not exist. This script is only designed to update a previous full build!
+
+:end