Visual Studio project compatibility and VisualStudioVersion

One of the most requested features of Visual Studio 2012 was the ability to open projects in both VS 2012 as well as VS 2010 (requires VS 2010 SP1). In case you haven’t heard we did implement that feature. You may be wondering how we were able to do this and how this may impact you. If you open the .csproj/.vbproj for a Web Project created in VS20...