I had the same issue on VS2013. I had to update to VS2013 Update 5 and get the latest nuget distro for VS2013 at
https://dist.nuget.org/visualstudio-2013-vsix/v2.12.0/NuGet.Tools.vsix
Once that was done, I rebooted Visual Studio. After that I was able to use the Automapper 5.0.2 package