other notes on NuGet

1. The items in the "Packages" folder should not be checked into source control.
2. If a bad reference is lingering, check the App.config of the project's folder. Version numbers of NuGet-driven dependencies are kept here.
3. Add a different package source
   
   1. Go to: Tools > Library Package Manager > Package Manager Settings
   2. Select "Package Sources"
   3. Add a source