Resizing and moving cropper using keyboard

I had a task to crop over 100 images and it was damn hard with just using current way of editing textboxes. I've prepared a patch, which enables using keyboard to manage size and position of cropper.

Now, you can increase and decrease value of selected text box by pressing up and down arrow. If you tired to switch textboxes to edit values, you could just hold CTRL and move the box in any direction you like. Doing the same with SHIFT could resize box in any direction.