Dashboard: history stack for undo/redo

[chetbae]

For undoing and redoing actions:

One possible solution is to create an IFolder stack of size ~20 (for 20 actions). For each action, eg Move, Rename, etc., push the root onto the stack. On undo, assign the last state to the root which will save to local storage, update dashboard, etc. Similar for redo, and add event listener for keybindings.