title: NuGet auto package restore does not work with MSBuild
body: <p>I'm trying to build a solution with <code>packages</code> content missing (except <code>repositories.config</code> inside) with MSBuild 12.0. I expect it to auto restore all missing packages before building but this is not the case - MsBuild reports tons of errors: </p>
  
  <blockquote>
    <p>"are you missing a using directive or an assembly reference?" </p>
  </blockquote>
  
  <p>NuGet Manager is 2.7 (I see this in Visual Studio 2013 about box). I even tried to pass <code>EnableNuGetPackageRestore=true</code> parameter - no luck. What am I missing?</p>