Ready: Strong consistency update

- [x] Configs in `advanced.config`
- [x] `riak-admin` interface for ensemble
- [x] Implementation details

Heads up to @andrewjstone, @engelsanchez, and @jtuple when he's back.
This paragraph should be removed as it was re-written above. We should also probably go back and modify the above re-write to take into consideration my comments about ring-size/num nodes, etc...