Do you want to start over, or rescue your old game?
If you want to grab the raw world data, try opening the browser's dev console and typing in localStorage.getItem("mosi-state") - that should return a big ugly string, and if you send it to me I can clean it up so you can re-import it.
If you just want to start over from scratch, type in localStorage.removeItem("mosi-state") - that should clear any old data that might be messing with the new version.