Support for HEIF EXIF data

[jmbowman]

Newer iPhones default to capturing photos in *.heic files using the HEIF format. These photos still use EXIF metadata, and it looks like the libheif-rs crate can parse it out of such files. Could the EXIF support in fselect be reasonably extended to cover HEIF files as well? libheif-rs depends on the libheif C++ library and its dependencies, so this probably would have an impact on build complexity unless it was a compile-time option.

I'm trying to find anything that can sort a folder of mixed HEIF and JPEG photos by date taken, and not finding much smaller than full-blown photo management databases.

[jhspetersson]

Support added in the master. Release version will follow in a couple of weeks.