[REQUEST] Use formatters about pytermgui

[bczsalba]

I do use black for python, and since the module itself doesn't really have any YAML files included I never found it important enough. I try to keep the example files pretty, however. Where did you experience problems with this?

[developomp]

This change is not necessarily for the users but for the contributors. So even if this will not change anything for how the library will be used, but it'll keep things consistent when this project gets more contributors. The formatters used are listed in the CONTRIBUTING.md file as well as other contributor guidelines.

[bczsalba]

That's really my biggest issue here, not having the contribution guidelines. I keep having to tell everyone about Pylint & Mypy, as well as black.

I do want to get it up soon, but at the moment I am focused on some other projects, hence the slowing down of commits recently.

[developomp]

Closed in pr #31