[tbot] Release 0.8.1

[Harald Seiler]

Hello!

I'm releasing tbot 0.8.1, to flush all the changes that have accumulated
in the last months.  I have a few big new features waiting to be added
(interactive commands and a good U-Boot test/py integration) but
I wanted a release before merging them.

Most changes were bug fixes and small features.  A full overview is in
the changelog [1].  Docs are on https://tbot.tools/ and available in PDF
form as well [2].

Additionally, I added an empty `tbot_contrib` module.  This is meant to
be a home for testcases that don't really belong into tbot core, but are
still useful for a lot of people and thus should be distributed
alongside tbot.  Feel free to send patches for any existing code you
have which you think would fit in!

Because of this new module, if you have been using the `develop`
installation of tbot, you need to reinstall using

    pip3 uninstall tbot
    python3 setup.py develop --user

otherwise, just update as usual, using

    git pull
    python3 setup.py install --user

[1]: https://github.com/Rahix/tbot/releases/tag/v0.8.1
[2]: https://github.com/Rahix/tbot/releases/download/v0.8.1/tbot.pdf
-- 
Harald