DIff against 7.15

zpaqfranz v51.31-experimental snapshot archiver, compiled Jun 4 2021 Key differences from ZPAQ 7.15 and zpaqfranz @2021-06-17

First goal: doveryay, no proveryay (trust, but verify). As a storage manager I need to be sure that my backups are perfect, so 'verify' is the objective of my zpaq fork.

Second: do not break compatibility with 7.15.

Third: most useful output: 7.15 is often cryptic but not very useful.

Fourth: pack everything needed for a storage manager (compare directories, hashing, duplicate find, fix of utf-8 filenames, wiping etc) in a single program.

Fifth: 'smart' support for strange filenames and paths, Windows and non-Windows.

Sixth: smooth with ZFS (I almost always use FreeBSD servers)

Seventh: run on multiple systems commonly used in storage (ESXi, non-Intel QNAP NAS).