http://blogs.msdn.com/b/visualstudio/archive/2010/07/06/debugging-msbuild-script-with-visual-studio.aspx
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSBuild\4.0 key to have debuggerenabled=true
用/debug启动msbuild
原文：http://www.cnblogs.com/rickerliang/p/4775341.html