pip packages names should not use underscores

[SubActif]

I just wanted to let people know that it would be better not to use an underscore in the module name.
They are discouraged in PEP8.

PIP transforms underscore into dash
pip list displays triangle-check

Some people, knowing this, are likely to try to use it like this:
python -m triangle-check path\to\backup
intead of
python -m triangle_check path\to\backup