Undoing after duplicating a screen should remove the screen again

[Esshahn]

• draw something
• duplicate the screen
• hit undo

Expected result:

• last action gets undone (the duplicated screen)

What happens:

• the duplicated screen is "reset" to a blank screen with default c64 blue colors

[nurpax]

I couldn't figure out how to do this with redux-undo since Petmate uses multiple undo stacks. Manipulating the screens (deletion, duplication) is not undoable at all, which is a bit of a bummer because deleting a screen cannot be undone.

If we had only a single undo stack, it'd be easy to undo/redo screen ops too.

An alternative that would work would be to have a separate undo stack for screens. Then screen operations like dupe or delete could fade in some sort of gmail style undo status bar where you'd have a button to undo the screen operation.