Suggestion: Save a backup of levels before they are overwritten

[slothybutt]

Misclicks, accidents, changes of heart, and (hopefully not) software errors can all happen when editing levels with Chaoshead, especially since there is no undo button to go back and fix your mistakes. I think it would be nice (and easy to implement) to have Chaoshead store backups of levels locally before it overwrites them.
In theory, these backups probably do not need to be deleted as level file size is generally pretty small. I do think that it'd be better to only save one backup per level per session, though, to avoid making a bunch of files by spamming the save button.

tl;dr: I think it'd be nice for the first pre-save backup per level per session to not be deleted (and to be saved with some sort of session id or time in the file name to reduce name collisions)