Entity Framework 6 where did key and column attributes go

I'm upgrading from Entity Framework 4.1.0.0 to Entity Framework 6 and I'm having a really hard time tracking where all of the old classes went and what namespace things are in these days.

I've got a class that looks like this and was using these attributes but now I

[Key, Column(Order = 1)]
public int PersonID { get; set; }
[Key, Column(Order = 2)]
public int WorkoutID { get; set; }
etc...

1. Can't figure out what namespace the attributes are in
2. Even figure out if I'm supposed to be using them
3. Can't nuke the EF class lib and rebuild it because the DB is code-first - I think..
   1. Disclaimer: I've never really worked from code-first because I like being able to rebuild my edmx file from scratch

Can anyone point me in the right direction? MSDN docs have some up short, the EF 6 upgrade guide (found here: http://visualstudiomagazine.com/articles/2014/03/01/whats-new-in-entity-framework-6.aspx) doesn't contain what I need and you'll all my last hope (not really - I'll keep looking no matter what)