Crop screen updates

•⁠ ⁠add CMD-Z/Shift-CMD-Z undo/redo keyboard shortcuts (and undo/redo buttons)

•⁠ ⁠⁠Reset should also reset the aspect ratio

•⁠ ⁠⁠double click the slider to return to 0

•⁠ ⁠⁠X to switch the aspect ratio between horiz/vertical versions (like 5:4 vs. 4:5)?

• Clicking on the slider should take you right to that point