The gaphical pemissions view in the permissions editor should support an Undo function

Current Situation

• Changes to permissions are immediately applied to shiro.ini by the editor. If a user arbitariry hits the wrong "battery" for a permission in the graphical permissions view then all previous settings are lost.

Desired Behavior

• An undo function should be available for the graphical permissions view. The function should be available from an button "Undo". Hitting this button should undo the previous click that a user has performed. Repeatedly hitting this button brings the user back to the original state - step by step.