Replace DenseRowTextStorage with raw mr job

@markhibberd I haven't done anything significant here (yet), expect for order the dictionary the way it was. I'm assuming there is more we want to do as well but you didn't get time. I'm happy to finish it up, and might look more closely at what you've done after lunch.

/cc @raronson 
> Not sure what you mean by order of dictionary - I thought I had changed i to be different so it wasn't so reliant on the text representation - but maybe not

Oh you had, and I went and broke it. What did we want the order to be? My only concern is that the order of `dict.definitions` is non-deterministic because we use `Map` in thrift. It's easy to change in this once place now.