Support Exiv2 0.28+
Use the new types for the image pointer and exception class, and the different method for the EXIF_ORIENTATION_KEY exif metadata, as available in the new Exiv2 version, keeping the support for older versions.
Fixes #123
Use the new types for the image pointer and exception class, and the different method for the EXIF_ORIENTATION_KEY exif metadata, as available in the new Exiv2 version, keeping the support for older versions.
Fixes #123