Fix strange items on the undo and redo stack#14

When drawing the undo stack keeps track of all the modifications to the entities array. But during a tools state flow, the entities array is sometimes temporarily manipulated to draw the preview state of the tool. for instance, the rotation tool show the roated entities during the rotation, but before the endpoint of the rotation has been clicked. We should avoid tracking these changes to the entities array. Possible way to do that would be to keep track of an extra boolean in the setEntities function to track if that change should be added to the undo stack Only the end result of a tool would then need to be tracked in the undo state