Move Scalding to 2.10/2.11

So this is just the beginning, but it's a big chunk of the work. I've been doing it between other things.

The big things I've done are to get scalding-core and scalding-hadoop-test working. Note: the DistributedCache tests in scalding-core had a dependency on mockito.... for now I commented it out. Do we want to depend on mockito just for one test? That said, rewriting is going to be a slight pain. So I'm not sure what we want to do there.

Either way, this is to get the ball rolling. I haven't started the 2.11 work becasue we need a new algebird release...but the scalatest migration stuff is enough for the time being!
It's certainly not ideal, but I think that the possibility for confusion is fairly minimal. There are a couple of different ways to do this, most of which required more refactoring than this did, so I went with this approach. I think it is worth having a better approach in the future, but this one maintains semantics very close to what exists today (just with a dummy index value in the spec name)