Accept all JPEG SOF variants

Previously I've only encountered JPG images using SOF0 or SOF2 (FF C0 or FF C2). However, #10 brought to my attention an SOF1 image. I looked up the SOF marker definition and it looks like C0 to CF are all valid SOF markers, so I've changed the check to accept them all.

I am missing tests for C3 to CF so I can't guarantee they are all the same, but if something breaks please open an issue. As of right now all JPG test images in the repo are working.