flatpak: update files following names change + Python 3 update: - `build_manifest.py` has been fixed to work with recent SàT/Libervia - filenames/scripts have been udpated to reflect project name change - installation now uses `requirements.txt` when dev version is requested - there are now 3 types of commands wrapper: * `libervia_wrapper.py` uses `pb` bridge, starts backend before frontend, and stops it when frontend is stopped. It's used by `Libervia Desktop` (Cagou) * `libervia_wrapper-dbus.py` uses `dbus` bridge, starts backend before frontend, and stops it when frontend is stopped. It's used for `Libervia TUI` (Primitivus) * `libervia_wrapper-dbus.py` uses `dbus` bridge, starts backend if necessary and doesn't stop it (to avoid waiting for backend start next time). It's used by `Libervia CLI` (jp).

// Big Integer Library v. 5.5
// Created 2000, last modified 2013
// Leemon Baird
// www.leemon.com
//
// This file is public domain.   You can use it for any purpose without restriction.
// I do not guarantee that it is correct, so use it at your own risk.  If you use 
// it for something interesting, I'd appreciate hearing about it.  If you find 
// any bugs or make any improvements, I'd appreciate hearing about those too.
// It would also be nice if my name and URL were left in the comments.  But none 
// of that is required.