[World Creator] Action Undo / Redo (Ctrl+Z / Ctrl+Y)

Hey there!

Suggest to add in World Creator very usefull functional: Undo / Redo.

For now looks like map designer not have chance for mistake, sometimes we rotate / translate / add objects just for check how it's will looks, sometimes we doing color painting of terrain for understand if this will be better, sometimes we cloning multiply objects by mistake and many other examples where CTRL+Z it's must-have thing.

In most nice way (as i can imagine) this feature can be implemented as part of Action History, which can be killer feature.



With best regards.