Add "undo button" or equivalent for when the user changes x,y,z, scale values

[fsdias]

When an inexperienced user is playing with the parameters it is easy to completely mess up the the slides. I would be useful to have a button for reverting those changes.

A simple undo button can be useful under certain circumstances but it would probably be better to have a "revert to previous state". Maybe add an auto-save option and include a button for reverting to the previous save.