Always create state.yaml

[CalSimmon]

As it stands right now, the replicator seems to only create the state.yaml if it completes successfully. On any failure, it doesn't create file. It's not a big deal if I only want a small subset, but if I'm doing a major pull (100s to 1000s of the images), then it's a huge risk. It would be awesome to have it add to the state.yaml after each successful download so you don't have to restart the entire process if it fails at 750/1000.

[ryanolson]

That seems like a great addition.