It's currently placed in $(SolutionDir)\Packages\ , which is not a bad place per se, but if you don't want to check that folder into your source control, it's a problem.
A trivial work-around would be to search for it in $(SolutionDir) if it's not found in the Packages folder. That would permit it to be moved up a level and the source control repository can remain blissfully unaware of the packages folder.
Comments: I came up with code changes for using solution level repositories.config file (with minimal code changes) see: https://nuget.codeplex.com/SourceControl/network/forks/kfrajtak/NugEt/changeset/3dfe822394d4610d5ecec2ab9822dd4528e8b2e2
A trivial work-around would be to search for it in $(SolutionDir) if it's not found in the Packages folder. That would permit it to be moved up a level and the source control repository can remain blissfully unaware of the packages folder.
Comments: I came up with code changes for using solution level repositories.config file (with minimal code changes) see: https://nuget.codeplex.com/SourceControl/network/forks/kfrajtak/NugEt/changeset/3dfe822394d4610d5ecec2ab9822dd4528e8b2e2