Expected Behavior

crop and fullsize_crop should use the upper-left corner and width/height of the cropping rectangle.

Current Behavior

It uses the two corners' coordinates, which makes no sense if the corner specified (r,b) is to the left or above the corner specified by (l,t).

Context

x,y,w,h coordinates maks more sense intuitively and matches the vast majority of image processing software. The main reason to go with l,t,r,b is that it maps directly into PILlow, but that isn't a good reason to use it.