Auto handle exceptions of crop region

[din14970]

It seems to me (x,y)min and (x,y)max can be turned into (x, y)1 and (x, y)2 as the order should not matter. Internally, xmin is then min(x1, x2). Additionally, out of bounds can be automatically dealt with (x or y > width or height --> x or y set to width or height) instead of throwing errors. In this way, the show cropped region button could be removed and included in the update preview button -> the crop region shows up in the image when the apply crop checkbox is on. Now with the two buttons it's a bit confusing how the preview is getting updated.