create_cropped (Imlib2::Image)

    /*
     * Return a cropped copy of the image
     *
     * Examples:
     *   x, y, w, h = 10, 10, old_image.width - 10, old_image.height - 10
     *   new_image = old_image.crop x, y, w, h
     *
     *   rect = [10, 10, old_image.width - 10, old_image.height - 10]
     *   new_image = old_image.crop rect
     *
     *   x, y, w, h = 10, 10, old_image.width - 10, old_image.height - 10
     *   new_image = old_image.create_cropped x, y, w, h
     *
     *   rect = [10, 10, old_image.width - 10, old_image.height - 10]
     *   new_image = old_image.create_cropped rect
     *
     */
    static VALUE image_crop(int argc, VALUE *argv, VALUE self) {