Undo Refinements and More Memory

There is now a button to undo refinements you don't like. If you refine a world and the results aren't what you expected, you can click the undo button to go back to the previous version. This is a big quality-of-life improvement for anyone who likes to experiment with refinements.

We also made it so the system can remember all of the changes you have made to your world. So now you can reference previous versions and make changes based on those previous versions. For example, "Add in the buildings from before". This is a big improvement for anyone who likes to iterate on their worlds and make changes based on previous versions.