I get a message saying the following:
Error 1 Package restore is disabled by default. To give consent, open the Visual Studio Options dialog,
I did not seem to have the "Package Manager" node under Tools->Options [this was in Visual Studio 2013 :-)]. To get that node in there, I browsed to Tools -> Extensions and Updates and searched for nuget. Installing "NuGet for Visual Studio 2013" got me the node and the option to allow package restore!