Try to handle syntax error in tests the best we can

Improve fake robustness. Stop supporting Debian. Start supporting NixOS

FIX issue with set -u

Add setup_suite and teardown_suite for file level setup/teardown

bash_unit changes the current working directory before loading the te…

…st file

One can now declare todo tests that are not yet implemented

FIX bash-unit#39 correct version number in bash_unit -v FIX bash-unit#19

 genereate man pages at release time

ADD FORCE_COLOR environment variable

This is usefull if you want to force color output
even if out of a tty. For instance when running tests
in a gitlab-runner.

Prettier output with unicode colored characters when in interactive m…

…ode.

Closes bash-unit#25

Document -f tap format.