Port to Python3

[LazyKent]

Python2 is planned to be removed from distribution of openSUSE (and Fedora, and FreeBSD).
Then want to have the djvusmooth program working using Python3 runtime.

[LazyKent]

To add a dramatic effect.
https://lists.opensuse.org/opensuse-factory/2020-01/msg00095.html

[eldarkg]

Ubuntu 20.04LTS removed the djvusmooth from official repository

[yurivict]

FreeBSD is removing djvusmooth on 2020-08-15 because it uses the EOLed version of python (2.7).

[Skif-off]

Debian, Ubuntu and FreeBSD still have Python 2.

Debian/Ubuntu and based on:
Build python-djvu: https://salsa.debian.org/python-team/packages/python-djvulibre/-/tags/debian%2F0.8.4-1
Note: Needs python-is-python2 (for building only).
Build djvusmooth: https://salsa.debian.org/python-team/packages/djvusmooth/-/tags/debian%2F0.3-1
Works fine for me (Xubuntu 20.04).

Other way (but v.0.8.2 and v.0.2.19):
python-djvu_0.8.2-2_amd64.deb from http://old-releases.ubuntu.com/ubuntu/pool/universe/p/python-djvulibre/
djvusmooth_0.2.19-3_all.deb from http://old-releases.ubuntu.com/ubuntu/pool/universe/d/djvusmooth/

[ghost]

How much work would that port involve? After all, python is still python.