Undo Button?

So lets say I'm rearranging my village and I make a slight mistake and I have to restart everything all over and this could be fixed by an undo button! Why can't supercell just implement this? Reply if you have the same problem!

*THIS POST IS NO LONGER RELEVANT AS THERE IS NOW A VILLAGE EDIT MODE*

I have occurred this problem many times and an undo button would be very useful. Good idea!