Poetry and pyproject.toml are good things, let's use them.
Withing this issue of later we can get rid of setup.py, requirements.txt, dev-requrements.txt and MANIFEST.in replacing it with just one tiny boi pyproject.toml.
Add pyproject.toml with poetry settings.
Use poetry in makefile to install, develop, run tests and so on instead of using virtualenv directly.
Update .travis.yml to install poetry before all the things.
Poetry and pyproject.toml are good things, let's use them. Withing this issue of later we can get rid of setup.py, requirements.txt, dev-requrements.txt and MANIFEST.in replacing it with just one tiny
boipyproject.toml.