title: clean VS 2015 Enterprise + Xamarin Install: error: NuGet Package restore failed for project
body: <p>Hello i have a clean Installation of VS2015 Enterprise + Xamarin.</p>
  
  <p>Then just start a New Projekt (Xamarin Forms Portable) add a Button and want to test on Android Emu.</p>
  
  <p>Then i get the Following 5 Errors and i don't know, how to solved it. </p>
  
  <p><a href="http://i.stack.imgur.com/zTnqE.png" rel="nofollow">errors</a></p>
  
  <p><a href="http://i.stack.imgur.com/NrjvQ.gif" rel="nofollow">start Projekt</a></p>