HEIF EXIF support

[leslie-wang]

Based on apple's reply, https://forums.developer.apple.com/thread/89759, seems like HEIF stores EXIF into mp4 box/atom container. Just wonder if you have any plan to support it?

[rwcarlsen]

I had noticed this recently, but I don't think I've got time for it in the near future, but I do think that this probably should be close to priority #1 going forward.

[mzimmerman]

Is it as simple as using another go library to do it? :) https://github.com/jdeng/goheif