EXEC: 'Unity' already has a dependency defined for 'CommonServiceLocator'.
You probably have NuGet.exe that's out of date. Here is how to update with Visual Studio 2013/2012.
Step 1: Go to the Solution folder on your local and remove the .nuget folder (or rename to .nuget.bak until later in case you need some custom stuff from .config or .targets).
Step 2: Open solution in Visual Studio.
Step 3: Right-Click Solution from Solution Explorer and select the "Enable NuGet Package Restore" option.
*say yes in the dialog that follows
There you have it! The easiest way to update nuget in a Visual Studio solution.