I started a new MVC project with EntityFramework -Version 6.1.2
using Visual Studio 2013 latest update. I made a couple of migrations and updated the database.
OK so I had this problem with an EF6 project I started in VS2013 and upgraded to VS2015 RC. The commands were available if I opened it in VS2013 but not in VS2015. What I found to solve the problem quickly and easily was to use the reinstall package command:
Update-Package –reinstall EntityFramework
This fixed any command missing errors and then allowed me to start database updates and create new migrations within VS2015.