//Add a step, remove all steps before the last revert
public void uAdd(Step step, int stepNum, modified type)
{
inputs.Push(new uInput(step, stepNum, type));
}
readonly public int stepNum; // Step number of the step that was changed
public uInput(Step step, int stepNum, modified type)
{
this.stepNum = stepNum;
this.step = step;
this.type = type;
}