message: `to_image` now only requires `I::Target: GenericImageView`
diff: @@ -987,7 +987,7 @@ impl<I> SubImage<I> {
  pub fn to_image(&self) -> ImageBuffer<DerefPixel<I>, Vec<DerefSubpixel<I>>>
  where
  I: Deref,
  - I::Target: GenericImage + 'static,
  + I::Target: GenericImageView + 'static,
  {
  let mut out = ImageBuffer::new(self.xstride, self.ystride);
  let borrowed = self.image.deref();
  