IMG2IMG: Context-sensitive aware width/height sliders based on values derived from the crop overlay tool

[cragginstylie]

The crop overlay would be much more effective and intuitive if the height/width sliders would follow the dimensions as set by the selection tool. As it stands now, one must guess the overlay selection values, and then change the sliders to match. After the sliders have been set from the crop selection tool, they can still be adjusted on the whims of the user to alter the visual affect