Improve file sorting

Better documentation

Remove duplicated code

Change comments so that build constraints still work

Add copyright notices to the arch-specific files

Sort results Sort groups by size of a group file, and files from a same group by path.

Cosmetics (go fmt and comments...)

Get rid of the now useless sizeClass structure

Code cleanup

Fix hard link detection The previous algorithm was assuming all files of a size group, or none of them, would be hard links. For size groups with both hard links and regular files, the detection could fail.