heifload autorotate is now always on, and we always delete EXIF orientation tags. If a HEIC image fails to rotate upright, at least it's someone else's fault. see https://github.com/libvips/libvips/pull/1680
libvips test suite
This is in two parts: a few simple bash scripts in this directory are run on "make check", and a fancier Python test suite that's run by Travis on each commit.