some housekeeping. added linebreaks and descriptions
added handle_imageborders8Bit into image_processing.c and image_processing.h to replace copy_images.
renamed copy_images to copy_images8Bit
BTW: Should we start with a naming-convention to disinguish 8 bit and 16-bit-ready routines?
Basicly we only need to change the datatype for the pointer array(s), but this would kill backward compatibility.
added description for split
added description for enhance
added some more descriptions